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A098541
Column 2 of triangle A098539, which shifts left one column under the matrix square.
2
1, 4, 20, 140, 1460, 23884, 639156, 28895052, 2260707508, 311748794188, 76846781851828, 34240231941576524, 27825184844063467700, 41547951604100714698572, 114705005843089453002549428
OFFSET
0,2
PROG
(PARI) a(n)=local(A, B, C, m); A=matrix(1, 1); A[1, 1]=1; for(m=2, n+3, B=A^2; C=matrix(m, m); for(j=1, m, for(k=1, j, if(j<3 || k==j || k>m-1, C[j, k]=1, if(k==1, C[j, k]=B[j-1, 1], C[j, k]=B[j-1, k-1])); )); A=C); A[n+3, 3]
CROSSREFS
Sequence in context: A292932 A187116 A340903 * A376528 A004204 A160567
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 13 2004
STATUS
approved