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 A153312 Coefficient triangle sequence of a polynomial recursion: p(x,n)=(x + 1)*(p(x, n - 1) + 3^(n - 3)*Sum[x^i, {i, 1, n - 2}]); Row sums approximate 2*3^n. 0
 2, 3, 3, 2, 14, 2, 2, 25, 25, 2, 2, 36, 86, 36, 2, 2, 47, 140, 140, 47, 2, 2, 76, 241, 334, 241, 76, 2, 2, 159, 479, 737, 737, 479, 159, 2, 2, 404, 1124, 1702, 1960, 1702, 1124, 404, 2, 2, 1135, 2986, 4284, 5120, 5120, 4284, 2986, 1135, 2, 2, 3324, 8495, 11644, 13778 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Row sums: {2, 6, 18, 54, 162, 378, 972, 2754, 8424, 27054, 89100,...}. LINKS FORMULA p(x,n)=(x + 1)*(p(x, n - 1) + 3^(n - 3)*Sum[x^i, {i, 1, n - 2}]). EXAMPLE {2}, {3, 3}, {2, 14, 2}, {2, 25, 25, 2}, {2, 36, 77, 45, 2}, {2, 65, 167, 176, 74, 2}, {2, 148, 313, 424, 412, 157, 2}, {2, 393, 704, 980, 1079, 812, 402, 2}, {2, 1124, 1826, 1684, 2788, 2620, 1943, 1133, 2}, {2, 3313, 5137, 3510, 6659, 7595, 4563, 5263, 3322, 2}, {2, 9876, 15011, 8647, 10169, 20815, 18719, 9826, 15146, 9885, 2} MATHEMATICA Clear[p, n, m, x]; p[x, 3] = 2*x^3 + 25*x^2 + 25*x + 2; p[x, 4] = 2*x^4 + 36*x^3 + 86*x^2 + 36*x + 2; p[x_, n_] := p[x, n] = (x + 1)*(p[x, n - 1] + 3^(n - 3)*Sum[x^i, {i, 1, n - 2}]); Table[ExpandAll[p[x, n]], {n, 0, 10}]; Table[CoefficientList[p[x, n], x], {n, 0, 10}]; Flatten[%] CROSSREFS Sequence in context: A153290 A153516 A153311 * A153283 A153288 A153479 Adjacent sequences:  A153309 A153310 A153311 * A153313 A153314 A153315 KEYWORD nonn,uned,tabl AUTHOR Roger L. Bagula, Dec 23 2008 STATUS approved

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Last modified December 5 23:39 EST 2019. Contains 329784 sequences. (Running on oeis4.)