0,2
Equals one-half of column 0 of A107719 shift 1 place left.
Table of n, a(n) for n=0..16.
(PARI) {a(n)=if(n<0, 0, (matrix(n+2, n+2, m, j, if(m>=j, if(m==j, 1, if(m==j+1, -3*j, polcoeff(1/sum(i=0, m-j, prod(r=0, i-1, 3*r+1)*x^i)+O(x^m), m-j)))))^-1)[n+2, 2])}
Cf. A107717, A107719.
Sequence in context: A141372 A152170 A087659 * A000406 A032119 A145170
Adjacent sequences: A107715 A107716 A107717 * A107719 A107720 A107721
nonn
Paul D. Hanna, May 30 2005
approved
