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 A139379 #8 Sep 24 2021 09:06:31
%S A139379 0,1,2,6,15,41,113,327,982,3066,9892,32820,111390,385042,1350722,
%T A139379 4795246,17191535,62139697,226167557,828085651,3047683955,11267975677,
%U A139379 41829610607,155848125601,582566960465,2184167358991,8211247681373
%N A139379 A Jacobsthal Catalan convolution.
%C A139379 Second column of A139377. Row sums of A139377 give a(n+1).
%F A139379 G.f.: xc(x)/(1-x-2x^2), c(x) the g.f. of A000108; a(n)=sum{k=0..n, A000108(k)*A001045(n-k)};
%F A139379 D-finite with recurrence n*a(n) +(6-5*n)*a(n-1) +2*(n-3)*a(n-2) +4*(2*n-3)*a(n-3)=0. - _R. J. Mathar_, Oct 25 2012
%K A139379 easy,nonn
%O A139379 0,3
%A A139379 _Paul Barry_, Apr 15 2008