A098541 Column 2 of triangle A098539, which shifts left one column under the matrix square.

1, 4, 20, 140, 1460, 23884, 639156, 28895052, 2260707508, 311748794188, 76846781851828, 34240231941576524, 27825184844063467700, 41547951604100714698572, 114705005843089453002549428

Offset

0,2

Links

Table of n, a(n) for n=0..14.

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

Cf. A098539, A098540.

Sequence in context: A292932 A187116 A340903 * A004204 A160567 A034216

Adjacent sequences: A098538 A098539 A098540 * A098542 A098543 A098544

Keyword

nonn

Author

Paul D. Hanna, Sep 13 2004

Status

approved