A217203 First column of A217202.

0, 1, 2, 7, 28, 131, 690, 4033, 25864, 180265, 1354458, 10898823, 93407828, 848739867, 8143768538, 82229315137, 871067808272, 9654457636241, 111688595475634, 1345725966256071, 16854833617813388, 219050429104638707, 2949276326665620482, 41076923039499915393

Offset

1,3

Links

Table of n, a(n) for n=1..24.

Formula

G.f.: T(0)/x - 1/x, where T(k) = 1 - x^2*(k+1)/( x^2*(k+1) - (1-2*x*k)*(1-2*x-2*x*k)/T(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Oct 19 2013

Prog

(PARI) lista(m) = {P = x; M = subst(P, x, 1);  print1(polcoeff(M, 0, q), ", "); Q = 2*x; M = subst(Q, x, 1); print1(polcoeff(M, 0, q), ", "); for (n=3, m, newP = n*q*Q+ 2*q*(1-q)*deriv(Q, q)+2*x*(1-q)*deriv(Q, x)+n*x*P; M = subst(newP, x, 1); print1(polcoeff(M, 0, q), ", "); P = Q; Q = newP; ); } \\ Michel Marcus, Feb 12 2013

Crossrefs

Cf. A217202.

Sequence in context: A127084 A362555 A252737 * A052319 A127783 A297195

Adjacent sequences: A217200 A217201 A217202 * A217204 A217205 A217206

Keyword

nonn

Author

N. J. A. Sloane, Sep 27 2012

Extensions

More terms from Michel Marcus, Feb 12 2013

Status

approved