This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A037128 #16 Jan 23 2015 04:20:59
%S A037128 0,2,6,18,66,214,666,2072,6306,19166,58020,175114,527358,1586122,
%T A037128 4766560,14316138,42981210,129009096,387158352,1161737214,3485735826,
%U A037128 10458256090,31376865294,94134790242,282412759224,847255054990,2541798719452,7625463267246,22876524019528,68629840494090,205890058352826
%N A037128 a(n) = nextprime(3^n) - nextprime(2^n).
%F A037128 a(n) = A014211(n) - A014210(n). - _Michel Marcus_, Jan 22 2015
%t A037128 Table[NextPrime[3^n] - NextPrime[2^n], {n, 0, 30}] (* _Vincenzo Librandi_, Jan 22 2015 *)
%o A037128 (PARI) a(n) = nextprime(3^n+1)-nextprime(2^n+1); \\ _Michel Marcus_, Jan 22 2015
%Y A037128 Cf. A014210, A014211.
%K A037128 nonn
%O A037128 0,2
%A A037128 _N. J. A. Sloane_
%E A037128 More terms from _Vincenzo Librandi_, Jan 22 2015