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 A147725 #7 Jan 03 2024 08:44:17 %S A147725 1,2,10,68,502,3770,28408,214202,1615330,12181748,91867102,692804690, %T A147725 5224704088,39401485202,297141621850,2240858259428,16899166494502, %U A147725 127443057596810,961096686931768,7247996548821002,54659905383139570 %N A147725 Row sums of triangle in A147724. %F A147725 a(n)=9*a(n-1)-11*a(n-2) for n>2, a(0)=1, a(1)=2, a(2)=10. G.f.: (1-7x+3x^2)/(1-9x+11x^2). %K A147725 nonn %O A147725 0,2 %A A147725 _Philippe Deléham_, Nov 15 2008