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 A192254 #14 Aug 23 2025 08:03:30 %S A192254 1,1,10,26,76,184,429,941,1994,4094,8208,16128,31169,59393,111818, %T A192254 208330,384620,704408,1280925,2314525,4158346,7432606,13223040, %U A192254 23424576,41335201,72679969,127373194,222545306,387732844,673762744 %N A192254 0-sequence of reduction of (n^2) by x^2 -> x+1. %C A192254 See A192232 for definition of "k-sequence of reduction of [sequence] by [substitution]". %F A192254 Empirical g.f.: x*(1-3*x+9*x^2-6*x^3+2*x^4)/(1-x)/(1-x-x^2)^3. - _Colin Barker_, Feb 10 2012 %t A192254 c[n_] := n^2; (* A000290 *) %t A192254 Table[c[n], {n, 1, 15}] %t A192254 q[x_] := x + 1; %t A192254 p[0, x_] := 1; p[n_, x_] := p[n - 1, x] + (x^n)*c[n + 1] %t A192254 reductionRules = {x^y_?EvenQ -> q[x]^(y/2), %t A192254 x^y_?OddQ -> x q[x]^((y - 1)/2)}; %t A192254 t = Table[ %t A192254 Last[Most[ %t A192254 FixedPointList[Expand[#1 /. reductionRules] &, p[n, x]]]], {n, 0, %t A192254 30}] %t A192254 Table[Coefficient[Part[t, n], x, 0], {n, 1, 30}] (* A192254 *) %t A192254 Table[Coefficient[Part[t, n], x, 1], {n, 1, 30}] (* A192255 *) %t A192254 (* _Peter J. C. Moses_, Jun 20 2011 *) %K A192254 nonn,changed %O A192254 1,3 %A A192254 _Clark Kimberling_, Jun 27 2011