A156172 Twice A002437.

2, 14, 610, 66734, 13631170, 4474847054, 2154541552930, 1430306187579374, 1252111529306645890, 1397549490970710103694, 1937106722774840873390050, 3264361741756845694953780014, 6572644038805857912224455865410, 15583184923914619905634967412688334, 42971525874172716914734880462487351970

Offset

0,1

Comments

Suggested by analogy with A000191.

Links

Table of n, a(n) for n=0..14.

Maple

Q:=proc(n) option remember; if n=0 then RETURN(1); else RETURN(expand((u^2+1)*diff(Q(n-1), u)+u*Q(n-1))); fi; end;
[seq(2*subs(u=sqrt(3), Q(2*n)), n=0..25)];

Crossrefs

Sequence in context: A012005 A342181 A294353 * A013036 A075044 A211891

Adjacent sequences: A156169 A156170 A156171 * A156173 A156174 A156175

Keyword

nonn

Author

N. J. A. Sloane, Nov 06 2009

Status

approved