OFFSET
0,2
PROG
(PARI) {a(n, q=2)=local(A=Mat(1), B); if(n<0, 0, for(m=1, n+2, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, if(j==1, B[i, j]=if(i>2, (A^q)[i-1, 2], 1), B[i, j]=(A^q)[i-1, j-1])); )); A=B); return(sum(k=0, n, A[n+1, k+1])))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 25 2005
STATUS
approved