I just did a search of GRETIL for ...a a....  ... and there are hundreds possibly thousands of occurances of this .  Here is a small sample.  Note the Brahmasutras and Mahabhasya with commentaries had hundreds but since I wasn't sure if sandhi had been broken in these for commentarial purposes I'm not including them in this following small sample:

 Rg Veda

Aufrechts edition compiled by H.S. Ananthanarayana and W. P. Lehman. <BR>

RV_01.077.04.1{25} sa no nṛṇāṃ nṛtamo riśāda agnirgiro 'vasā vetu dhītim<BR>

RV_01.094.05.2{30} citraḥ praketa uṣaso mahānasya agne ...<BR>

RV_01.105.03.1{20} mo ṣu deva adaḥ svarava pādi divas pari<BR>

RV_01.141.01.2{08} yadīmupa hvarate sādhate matirṛtasya dhena anayanta sasrutaḥ<BR>

RV_01.161.12.2{06} aśapata yaḥ karasnaṃ va adade yaḥ prābravīt protasma abravītana<BR>

RV_01.161.12.2{06} aśapata yaḥ karasnaṃ va adade yaḥ prābravīt protasma abravītana<BR>

RV_01.174.10.1{17} tvamasmākamindra viśvadha sya avṛkatamo narāṃ nṛpātā<BR>

RV_01.191.01.2{14} dvāviti pluṣī iti nyadṛṣṭa alipsata<BR>

RV_07.023.04.2{07} yāhi vāyurna niyuto na achā tvaṃ hi dhībhirdayase vi vājān<BR>

RV_08.005.03.1{01} yuvābhyāṃ vājinīvasū prati stoma adṛkṣata<BR>

RV_08.066.13.1{50} vayaṃ ghā te tve id vindra vipra api ṣmasi<BR>

RV_08.092.31.1{20} mā na indra abhyādiśaḥ sūro aktuṣvā yaman<BR>

RV_10.025.02.1{11} hṛdispṛśasta asate viśveṣu soma dha masu<BR>

RV_10.025.07.1{12} tvaṃ naḥ soma viśvato gopa adabhyo bhava<BR>

RV_10.088.07.2{11} tasminnagnau sūktavākena devā havirviśva ajuhavustanūpāḥ<BR>

RV_10.138.05.2{26} indrasya vajrādabibhedabhiśnathaḥ prākrāmacchundhyurajahaduṣa anaḥ<BR>

RV_10.151.03.1{09} yathā deva asureṣu śraddhāmugreṣu cakrire<BR>

RV_10.152.02.2{10} vṛṣendraḥpura etu naḥ somapa abhayaṃkaraḥ<BR>

Atharvaveda-Samhita, Saunaka recension with the Pada-Patha and Sayanacarya's commentary, Hoshiarpur 1960-1964<BR>

(AVŚ_3,19.8c) jáya amítrān prá padyasva jahy èṣāṃ váraṃvaraṃ mā́mī́ṣāṃ moci káś caná ||8||<BR>

(AVŚ_4,20.9a) yó antárikṣeṇa pátati dívam yáś ca atisárpati |<BR>

(AVŚ_4,36.10a) abhí táṃ nírr̥tir dhattām áśvam iva aśvābhidhā́nyā |<BR>

(AVŚ_6,39.3c) yaśā́ víśvasya bhūtásya ahám asmi yaśástamaḥ ||3||<BR>

(AVŚ_10,5.7a) agnér bhāgá stha apā́ṃ śukrám āpo devīr várco asmā́su dhatta |<BR>

(AVŚ_10,5.8a) índrasya bhāgá stha apā́ṃ śukrám āpo devīr várco asmā́su dhatta |<BR>

(AVŚ_10,5.9a) sómasya bhāgá stha apā́ṃ śukrám āpo devīr várco asmā́su dhatta |<BR>

(AVŚ_10,5.10a) váruṇasya bhāgá stha apā́ṃ śukrám āpo devīr várco asmā́su dhatta |<BR>

(AVŚ_10,5.11a) mitrā́váruṇayor bhāgá stha apā́ṃ śukrám āpo devīr várco asmā́su dhatta |<BR>

(AVŚ_10,5.12a) yamásya bhāgá stha apā́m śukrám āpo devīr várco asmā́su dhatta |<BR>

(AVŚ_10,5.13a) pitr̥̄ṇā́ṃ bhāgá stha apā́ṃ śukrám āpo devīr várco asmā́su dhatta |<BR>

(AVŚ_10,5.14a) devásya savitúr bhāgá stha apā́ṃ śukrám āpo devīr várco asmā́su dhatta |<BR>

(AVŚ_19,31.12a) grāmaṇī́r asi grāmaṇī́r utthā́ya abhíṣikto 'bhí mā siñca várcasā |<BR>

(AVŚ_20,131.2a) tásya anu níbhañjanam ||2||<BR>

maitrāyaṇīi-saṁhitā ṣchroeder's edition

ity uparikāṇḍe asurāṇāṃ nāma aṣṭamaḥ prapāṭhakaḥ samāptaḥ //MS_3,8.10//<br>

amanyanta, ayaṃ vāvedaṃ bhaviṣyatīti ta indra aichan hanāmemam iti so 'bravīt saṃdhā vai me

srājasūyenābhiṣiñcate tad vārtraghnam evaitat, devāś ca vā asurāś ca samayatanta tān agnis evaitat,

1 2 2 0910c pra na ayūṃṣi tāriṣat .. 184<BR>

 Samaveda

4 2 2 01 01a eta asṛgramindavastiraḥ pavitramāśavaḥ .<BR>

4 4 2 01 04a pra svānāso rathā ivārvanto na avasyavaḥ .<BR>

4 7 1 0703a ajījano amṛta martyāya amṛtasya dharmannamṛtasya cāruṇaḥ .<BR>

4 9 2 1101c pra na ayūṃṣi tāriṣat .. 1840<BR>

Gopatha-brāhmāṇa

(GBr_1,2.18q) tenāśva abhiṣṭūyeteti<BR>

gharmaṃ tāpyamānam upāsīta śastravad ardharcaśa āhāvapratigaravarjaṃ rūpasamṛddhābhiḥ_<BR>

(GBr_2,2.6kk) tad apy eṣābhyanūktā &lt;catvāri śṛṅgā [PS 8.13.3, sakala at GBr 1,2.16f]&gt;_iti || 6 ||<BR>

(GBr_2,4.4n) net svikṛta antarayāmeti_<BR>

(GBr_2,4.18w) net sviṣṭakṛta antarayāmeti_<BR>

Satapatha Brahmana

bhrātṛvyaṃ vardhayedyadatihṛtya sādayedyadya anāptāḥ sādayenno hābhistaṃ<BR>

upadadhāmi bhrātṛvyasya badhāyeti yadi nābhicaredyadya abhicaredamuṣya<BR>

atha dakṣiṇām paridadhāti | indrasya bāhurasi dakṣiṇo viśvasya ariṣṭyai<BR>

saptadaśa sāmidhenīḥ | iṣṭya anubrūyādupāṃśu tasyai devatāyai yajati yasyā iṣṭaṃ<BR>

rakṣasāmapahantā yadi madhyata asurarakṣasānyāsisaṃkṣantyagnireva tānyapahanti<BR>

Govind Kaul: Pradesasamgraha

punaś ca asya jalāśayasya pāścāttye taṭa ekā bṛhacchālā purātanakālīnena jyahāṃgīrarājñā sampāditā yasyām ādhunikarājñā jīrṇoddhārādikaṃ niramīyata |<br>

asminn eva achyabal iti sthānaṃ sarvajanamate priyaṃ sarvataḥ prakhyātaṃ ca bhavati |<br>

yasmin bhūbhāge 'syāgneḥ prādurbhāvaḥ sa bhūmibhāga atyuṣṇo hastādisparśenāpi lakṣyate |<br>

tatraikasya nandikṣetraṃ nāma anyasya kālakṣetraṃ nāma vartate |<br>

ato jñāyate puratāne kāle tat sarvam abhaviṣyad eva asyoktajalāśayadvayasya kāśmīrikagrāmīṇabhāṣayā nund kol iti nāmadvayaṃ sarvajanakathyamāṇaṃ bhavati |<br>

ayaṃ kāṣṭhabhedo jvālārahito 'pi pākādikriyaṃ sampādayaty eva asya grāmīṇānāṃ bhāṣaṇe viṭhur vā viṭhar kāṭh nāma bhavatīti ||<br>

kecana aśokenaiva rājñā ca pradeśe prathamato nirmāṇaṃ kṛtam iti svapustake likhamānā dṛśyante |<br>

tathā ca asya sarvasya jagataḥ sṛṣṭyāder ādāv api vartamāno yas sa ādikeśavaḥ |<br>

Sarvamatasamgraha edition by T. Ganapati Sastri

sādhanasāmānyābhāvena sādhyasāmānyābhāvasya vyāptirvyatirekaḥ yatra yatra agnirnāsti tatra tatra dhūmo 'pi nāstīti |<BR>

Badarayana: Brahmsutra, with Bhasya and Dipika, Adhyaya 1, Pada 1

paramānandādyātmakasya paramātmanaḥ pratibimbatayā svataścidānandādyātmakasya jīvasya anādyavidyākāmakarmādinimittabandhadhvaṃsāya nikhilajīvajaḍātmakāt prapañcāt paramārthato iti

Pururavas: Kadambarisvikaranasutramanjari

* anena vākyena anayoḥ kāryakāraṇasaṃgatiḥ upapāditā bhavati tathā cāyam arthaḥ