A099626 - OEIS

%I #6 Jun 13 2015 00:51:34

%S 0,1,2,7,18,52,142,397,1098,3051,8460,23480,65140,180749,501498,

%T 1391483,3860822,10712348,29722698,82469313,228821202,634892599,

%U 1761587480,4887741040,13561638120,37628431801,104404708402,289683694927

%N A transform of the Pell numbers.

%C A modified Chebyshev transform of A000129. Under this transform, the g.f. G(x) is mapped to (1/(1-x^2))G(x/(1-x^2)).

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,3,-2,-1).

%F G.f.: x/(1-2x-3x^2+2x^3+x^4); a(n)=2a(n-1)+3a(n-2)-2a(n-3)-a(n-4); a(n)=sum{k=0..floor(n/2), binomial(n-k, k)Pell(n-2k)}.

%K easy,nonn

%O 0,3

%A _Paul Barry_, Oct 25 2004