# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a192145 Showing 1-1 of 1 %I A192145 #8 Dec 04 2016 19:46:25 %S A192145 1,1,13,35,105,258,608,1344,2865,5910,11894,23444,45427,86755,163645, %T A192145 305397,564647,1035446,1885050,3409610,6131441,10968416,19528188, %U A192145 34617960,61125685,107540053,188567053,329625719,574558965,998836650 %N A192145 0-sequence of reduction of pentagonal numbers sequence by x^2 -> x+1. %C A192145 See A192232 for definition of "k-sequence of reduction of [sequence] by [substitution]". %F A192145 Empirical G.f.: x*(1-3*x+12*x^2-9*x^3+4*x^4)/(1-x)/(1-x-x^2)^3. [Colin Barker, Feb 11 2012] %t A192145 Remove["Global`*"]; %t A192145 c[n_] := n (3 n - 1)/2; (* pentagonal numbers, A000326 *) %t A192145 Table[c[n], {n, 1, 15}] %t A192145 q[x_] := x + 1; %t A192145 p[0, x_] := 1; p[n_, x_] := p[n - 1, x] + (x^n)*c[n + 1] %t A192145 reductionRules = {x^y_?EvenQ -> q[x]^(y/2), %t A192145 x^y_?OddQ -> x q[x]^((y - 1)/2)}; %t A192145 t = Table[ %t A192145 Last[Most[ %t A192145 FixedPointList[Expand[#1 /. reductionRules] &, p[n, x]]]], {n, 0, %t A192145 30}] %t A192145 Table[Coefficient[Part[t, n], x, 0], {n, 1, 30}] (* A192145 *) %t A192145 Table[Coefficient[Part[t, n], x, 1], {n, 1, 30}] (* A192146 *) %t A192145 (* by _Peter J. C. Moses_, Jun 20 2011 *) %Y A192145 Cf. A192232, A192146. %K A192145 nonn %O A192145 1,3 %A A192145 _Clark Kimberling_, Jun 27 2011 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE