OFFSET
0,2
PROG
(PARI) {a(n)=local(A=matrix(2, 2), B); A[1, 1]=1; for(m=2, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=j, if(j==1, B[i, j]=(A^3)[i-1, 1], B[i, j]=(A^3)[i-1, j])); )); A=B); return(sum(k=0, n, A[n+1, k+1]))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Dec 29 2004
STATUS
approved