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 A138392 #4 Feb 23 2015 17:24:12 %S A138392 1,3,12,128,2048,81920,5242880,805306368,206158430208,123145302310912, %T A138392 126100789566373888,295147905179352825856,1208925819614629174706176, %U A138392 11141460353568422474092118016,182541686432865033815525261574144 %N A138392 Hankel transform of A062992 with interpolated zeros. %F A138392 a(n)=2^(comb(n+1,2)+0^n-1)*(2+floor((n+1)/2)-0^n) %p A138392 A138392 := proc(n) %p A138392 2^(binomial(n+1,2)+0^n-1)*(2+floor((n+1)/2)-0^n) ; %p A138392 end proc: %p A138392 seq(%(n),n=0..13) ; # _R. J. Mathar_, Feb 23 2015 %K A138392 easy,nonn %O A138392 0,2 %A A138392 _Paul Barry_, Mar 18 2008