A156172 - OEIS

A156172

Twice A002437.

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

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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