As you can see from [this map][1] on the Wals.info site, there are many. More explanations on the [main page][2]. 

After a quick search I did, it surprised me to see some languages on this list that seemed to use the same word for one and the indefinite article, such as Dutch. I might be wrong, it seems, so you might want to look more in depth for the ones you want to study more.

Anyway, they are **102**. I'll list them below for ease of reference alphabetically and ordered according to the continent:

> ## Africa

![enter image description here][3]

> ## America

 - Hawaiian;
 - Lakohta;
 - Quileute;
 - Pipil
 - Rama;
 - Squamish;
 - Tzutujil;
 - Yaqui.

> ## Asia

 - Arabic (iraqi);
 - Armenian (eastern and western);
 - Byansi;
 - Cebuano
 - Coptic;
 - Japanese;
 - Mangghuer;
 - Nar-Phu;
 - Nias;
 - Qiang;
 - Tajik;
 - Thai;

> ## Europe

 - Albanian;
 - Breton;
 - Danish;
 - Dutch;
 - English (although technically "an" derives from the weak form of Old English **ān** ‘one.’);
 - Frisian;
 - Hungarian;

> ## Oceania

![enter image description here][4]


  [1]: http://wals.info/feature/38A?tg_format=map&v1=c00d&v2=c99f&v3=cd00&v4=dfff&v5=cfff
  [2]: http://wals.info/chapter/38
  [3]: https://i.sstatic.net/rqDxL.png
  [4]: https://i.sstatic.net/d2w0O.png