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 A137389 #12 Mar 27 2015 14:31:31
%S A137389 12,40,160,2176,10240,139264,655360,8912896,545259520,2684354560,
%T A137389 139586437120,2336462209024,10995116277760,149533581377536,
%U A137389 9147936743096320,585467951558164480,2882303761517117440,149879795598890106880,2508757194024499019776,11805916207174113034240
%N A137389 a(n) = 2^prime(n) + 2^prime(n+1).
%F A137389 a(n) = A034785(n) + A034785(n+1). [_R. J. Mathar_, Jun 15 2009]
%F A137389 a(n) = 4*A137781(n). - _Wesley Ivan Hurt_, Mar 27 2015
%e A137389 a(3) = 160 because 2^5 + 2^7 = 160.
%p A137389 A137389:=n->2^ithprime(n)+2^ithprime(n+1): seq(A137389(n), n=1..20); # _Wesley Ivan Hurt_, Mar 27 2015
%t A137389 f[n_] := 2^Prime[n] + 2^Prime[n + 1]; Array[f, 18] (* _Robert G. Wilson v_ *)
%t A137389 Table[2^Prime[n] + 2^Prime[n + 1], {n, 18}] (* _Stefan Steinerberger_, Apr 12 2008 *)
%Y A137389 Cf. A000040, A001043, A137781.
%K A137389 nonn,easy
%O A137389 1,1
%A A137389 _Max Sills_, Apr 10 2008
%E A137389 More terms from _N. J. A. Sloane_, Apr 10 2008