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 A139238 #13 Jul 02 2014 00:46:24
%S A139238 4,24,96,1920,6144,122880,393216,7864320,528482304,1610612736,
%T A139238 135291469824,2061584302080,6597069766656,131941395333120,
%U A139238 8866461766385664,567453553048682496,1729382256910270464,145268109580462718976,2213609288845146193920
%N A139238 First differences of Mersenne numbers A001348.
%C A139238 Also, first differences of 2^prime(n) = A034785(n). - _Wesley Ivan Hurt_, Jul 02 2014
%H A139238 Felix Fröhlich, <a href="/A139238/b139238.txt">Table of n, a(n) for n = 1..59</a>
%F A139238 a(n) = A001348(n+1) - A001348(n).
%F A139238 a(n) = A034785(n+1) - A034785(n). - _Wesley Ivan Hurt_, Jul 02 2014
%e A139238 a(2)=24 because A001348(2)=7 and A001348(2+1)=31 then 31-7 = 24.
%p A139238 A139238:=n->2^ithprime(n+1)-2^ithprime(n): seq(A139238(n), n=1..20); # _Wesley Ivan Hurt_, Jul 02 2014
%t A139238 Table[2^Prime[n + 1] - 2^Prime[n], {n, 20}] (* _Wesley Ivan Hurt_, Jul 02 2014 *)
%o A139238 (PARI) for(n=1, 20, d=2^prime(n+1)-2^prime(n); print1(d, ", ")) \\ _Felix Fröhlich_, Jun 30 2014
%Y A139238 Cf. A001348, A139228, A139231, A139234, A139239, A139240, A139241, A139242, A139243.
%Y A139238 Cf. A034785.
%K A139238 easy,nonn
%O A139238 1,1
%A A139238 _Omar E. Pol_, Apr 19 2008
%E A139238 a(10)-a(19) from _Felix Fröhlich_, Jun 30 2014