A286786 Column 1 of A286781.

1, 9, 91, 1063, 14193, 213953, 3602891, 67168527, 1375636129, 30741614905, 745133551611, 19485223248311, 547092691302545, 16422216867929457, 524970306508659691, 17809453107819266335, 639153386976421052481, 24196474723945543441769, 963736849031626750711451, 40289411871795861783689799

Offset

1,2

Links

Gheorghe Coserea, Table of n, a(n) for n = 1..210

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(1)

Crossrefs

Cf. A286781.

Sequence in context: A362728 A335508 A176735 * A123792 A022520 A020236

Adjacent sequences: A286783 A286784 A286785 * A286787 A286788 A286789

Keyword

nonn

Author

Gheorghe Coserea, May 16 2017

Status

approved