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Search: id:A113987
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A113987 Column 4 of triangle A113983; also a(n) = A113983(n+3,3) + [A113983^2](n+2,3). +0
5
1, 5, 21, 89, 401, 1969, 10633, 63297, 414857, 2984829, 23485909, 201272257, 1870901681, 18786935025, 203013976769, 2352251860561, 29124175447169, 384114020063301, 5380529664829157, 79829102054901081, 1251315569536252353 (list; graph; listen)
OFFSET

0,2

FORMULA

a(n) = [A113983^4](n, 0) + [A113983^5](n-1, 0) = A113995(n) + A113996(n-1).

PROGRAM

(PARI) {a(n)=local(A, B); A=Mat(1); for(m=2, n+5, B=matrix(m, m); for(i=1, m, for(j=1, i, if(i<3|j==1|j==i, B[i, j]=1, B[i, j]=A[i-1, j-1]+(A^2)[i-2, j-1]); )); A=B); A[n+5, 5]}

CROSSREFS

Cf. A113983, A113984 (column 1), A113985 (column 2), A113986 (column 3).

Sequence in context: A015448 A099843 A035011 this_sequence A164037 A125784 A154964

Adjacent sequences: A113984 A113985 A113986 this_sequence A113988 A113989 A113990

KEYWORD

nonn

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), Nov 12 2005

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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