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 A134137 #2 Mar 31 2012 13:20:14 %S A134137 1,3,9,15,-159,-3021,-36903,-381249,-3212415,-12995901,315857961, %T A134137 12457515663,304888863969,6280156107315,113710631625081, %U A134137 1717208752084479,15528594345353217,-265033870991715069,-22048996644203788215 %N A134137 Alternating row sums of triangle A049352 (S1p(4)). %F A134137 a(n)=sum(A049352(n,m)*(-1)^(m-1),m=1..n), n>=1. %F A134137 E.g.f.: 1-exp(-x*(3-3*x+x^2)/(3*(1-x)^3)). Cf. e.g.f. first column of A049352. %K A134137 sign,easy %O A134137 1,2 %A A134137 _Wolfdieter Lang_ Oct 12 2007