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 A026570 #14 Nov 29 2024 19:05:50 %S A026570 1,1,4,7,20,43,111,259,648,1565,3885,9533,23662,58547,145630,362151, %T A026570 903110,2253615,5633359,14094035,35304658,88511733,222115782, %U A026570 557819793,1401987930,3526066273,8874034647,22346581133,56304982154 %N A026570 a(n) = A026568(n,n-1), also a(n) = number of integer strings s(0),...,s(n) counted by A026568 such that s(n)=1. %C A026570 Also a(n) = T'(n,n-1), T' given by A026584. Also a(n) = number of integer strings s(0),...,s(n) counted by T' such that s(n)=1. %F A026570 Conjecture: (n+1)*a(n) -2*n*a(n-1) +(-3*n-1)*a(n-2) +2*(2*n-3)*a(n-3)=0. - _R. J. Mathar_, Jun 23 2013 %F A026570 If recurrence is correct then a(n) = (A026569(n+1)-A026569(n))/2 = A026585(n+1)/2. - _Mark van Hoeij_, Nov 29 2024 %Y A026570 Cf. A026568, A026569, A026584, A026585. %K A026570 nonn %O A026570 1,3 %A A026570 _Clark Kimberling_