Numbers k such that 7^k starts with k.

Terms

a(0) =3a(1) =5560a(2) =14350a(3) =76972a(4) =239123a(5) =2067170a(6) =19320438a(7) =748459491a(8) =1273027965a(9) =6925699528a(10) =7758433284a(11) =8408679517a(12) =32002385444a(13) =556647183084a(14) =973172636259