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

Author

Paul D. Hanna, Sep 13 2004

Keywords

• nonn

Crossrefs

Cf. A098539, A098540.

Programs

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]