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

Author

N. J. A. Sloane, Sep 27 2012

Keywords

• nonn

Crossrefs

Cf. A217202.

Programs

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

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

Extensions

More terms from Michel Marcus, Feb 12 2013