A048515 a(n) = T(n,n), array T given by A048505.
1, 5, 35, 160, 577, 1816, 5245, 14288, 37313, 94384, 232861, 563080, 1339249, 3141464, 7282493, 16711456, 38010625, 85786336, 192282301, 428342936, 948960881, 2091908680, 4590665245, 10032774640, 21843934657
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..2000
- Index entries for linear recurrences with constant coefficients, signature (9,-33,63,-66,36,-8).
Programs
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Magma
[(9*n^2 + n) * 2^(n-2) - n^2 + 1: n in [0..30]]; // Vincenzo Librandi, Sep 26 2011
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PARI
Vec(-(8*x^5-43*x^4+53*x^3-23*x^2+4*x-1)/((x-1)^3*(2*x-1)^3) + O(x^100)) \\ Colin Barker, Feb 25 2015
Formula
a(n) = (9*n^2 + n) * 2^(n-2) - n^2 + 1. - Ralf Stephan, Feb 05 2004
G.f.: -(8*x^5-43*x^4+53*x^3-23*x^2+4*x-1) / ((x-1)^3*(2*x-1)^3). - Colin Barker, Feb 25 2015