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 A192308 #19 Aug 23 2025 23:12:11 %S A192308 0,6,15,39,84,174,342,654,1221,2241,4056,7260,12876,22662,39627,68907, %T A192308 119244,205482,352770,603630,1029825,1752261,2974320,5037624,8515224, %U A192308 14367174,24200007,40699119,68348676,114629286,192009006,321250830,536903421,896410377 %N A192308 1-sequence of reduction of (3n) by x^2 -> x+1. %C A192308 See A192232 for definition of "k-sequence of reduction of [sequence] by [substitution]". %F A192308 a(n) = 3*A122491(n+1). %F A192308 G.f.: 3*x^2*(2-x)/(1-x)/(1-x-x^2)^2. - _Colin Barker_, Feb 11 2012 %t A192308 (* See A192307. *) %Y A192308 Cf. A192232, A192307, A122491. %K A192308 nonn,changed %O A192308 1,2 %A A192308 _Clark Kimberling_, Jun 27 2011 %E A192308 More terms from _Jason Yuen_, Aug 23 2025