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 A229113 Row sums of triangle A166890. 1
 1, 3, 14, 115, 1474, 26306, 605538, 17116241, 574398861, 22333212354, 987660842174, 48969675370286, 2690888441513773, 162333780684342177, 10667116965172284025, 758434434866124781819, 58015602766701416940599, 4750972163883049286678765, 414721061026426313701858479 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Triangle A166890 transforms diagonals in the table of coefficients of successive iterations of x*(1+x)^2 (cf. A166888). LINKS Table of n, a(n) for n=0..18. EXAMPLE Triangle A166890 begins: 1; 2, 1; 9, 4, 1; 78, 30, 6, 1; 1038, 364, 63, 8, 1; 18968, 6233, 986, 108, 10, 1; 443595, 139008, 20685, 2072, 165, 12, 1; 12681960, 3833052, 545736, 51494, 3750, 234, 14, 1; ... of which the row sums form this sequence. PROG (PARI) {a(n, k)=local(F=x, M, N, P, m=max(n, k), A166890); M=matrix(m+2, m+2, r, c, F=x; for(i=1, r+c-2, F=subst(F, x, x+2*x^2+x^3+x*O(x^(m+2)))); polcoeff(F, c)); N=matrix(m+1, m+1, r, c, M[r, c]); P=matrix(m+1, m+1, r, c, M[r+1, c]); A166890=P~*(N~)^-1; sum(k=0, n, A166890[n+1, k+1])} for(n=0, 25, print1(a(n), ", ")) CROSSREFS Cf. A166890. Sequence in context: A265001 A279429 A333797 * A180435 A256159 A122081 Adjacent sequences: A229110 A229111 A229112 * A229114 A229115 A229116 KEYWORD nonn AUTHOR Paul D. Hanna, Sep 13 2013 STATUS approved

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Last modified September 21 02:47 EDT 2023. Contains 365486 sequences. (Running on oeis4.)