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Search: id:A109318
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| A109318 |
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Column 2 of triangle T=A109316 where T(n,k) = [T^2](n-1,k) + [T^2](n-2,k-1) and T^2 is the matrix square of A109316. |
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+0
4
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| 1, 2, 8, 36, 176, 920, 5080, 29336, 175752, 1085496, 6877240, 44518520, 293513784, 1965904984, 13348449784, 91723622936, 636923476728, 4463989946072, 31545992160568, 224580029779608, 1609455072125816, 11603437881340888
(list; graph; listen)
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OFFSET
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0,2
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PROGRAM
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(PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+3, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, if(i==2, B[i, j]=1, B[i, j]=(A^2)[i-1, j]+if(j>1, (A^2)[i-2, j-1]))); )); A=B); return(A[n+3, 3])}
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CROSSREFS
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Cf. A109316 (triangle), A109317 (column 0), A109319 (row sums), A000108.
Sequence in context: A084868 A109980 A110837 this_sequence A113327 A129148 A081958
Adjacent sequences: A109315 A109316 A109317 this_sequence A109319 A109320 A109321
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Jul 07 2005
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