0,2

(PARI) {a(n)=local(A, B, C, m); A=matrix(1, 1); A[1, 1]=1; for(m=2, n+1, 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); sum(i=1, n+1, A[n+1, i])}

Cf. A098539, A098541.

Sequence in context: A125282 A020125 A076322 this_sequence A079574 A032262 A144259

Adjacent sequences: A098537 A098538 A098539 this_sequence A098541 A098542 A098543

nonn

Paul D. Hanna (pauldhanna(AT)juno.com), Sep 13 2004