A286787 Column 2 of A286781.

1, 23, 416, 7344, 134613, 2620379, 54636792, 1223392968, 29409134545, 757686550455, 20870680635528, 612964613117960, 19140704352872949, 633710701752022635, 22185391759982205904, 819180275431111135536, 31826528430233802890049, 1298154677953792936043447, 55473817874169725876166480

Offset

2,2

Links

Gheorghe Coserea, Table of n, a(n) for n = 2..211

Prog

(PARI)
A286781_ser(N, t='t) = {
  my(x='x+O('x^N), y0=1+O('x^N), y1=0, n=1);
  while(n++,
    y1 = (1 + x*y0 + 2*x^2*y0')*(1 - x*y0*(1-t))/(1-x*y0)^2;
    if (y1 == y0, break()); y0 = y1; );
  y0;
};
Kol(K, N=20) = {
  my(s = A286781_ser(N+K, 't+O('t^(K+1))));
  vector(N, n, polcoeff(polcoeff(s, K+n-1), K));
};
Kol(2)

Crossrefs

Cf. A286781.

Sequence in context: A016197 A199821 A009008 * A226847 A203147 A158453

Adjacent sequences: A286784 A286785 A286786 * A286788 A286789 A286790

Keyword

nonn

Author

Gheorghe Coserea, May 16 2017

Status

approved