

A104506


Column 1 of triangle A104505, which is equal to the righthand side of the triangle A084610 of coefficients in (1+xx^2)^n.


1



0, 1, 2, 0, 8, 15, 6, 77, 120, 117, 770, 946, 1728, 7735, 6930, 22800, 76960, 42245, 282150, 751640, 125800, 3341205, 7145710, 2002725, 38228232, 65418925, 55550014, 424605078, 566938400, 936604097, 4587287310
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OFFSET

0,3


LINKS

Table of n, a(n) for n=0..30.


FORMULA

G.f.: ( (1x)/sqrt(12*x+5*x^2)  1)/(2*x). a(n) = (1)^n*n*A007440(n) (reversion of g.f. for Fibonacci numbers).
a(n)=sum{k=0..floor(n/2), C(n, k)C(nk, k+1)(1)^k}  Paul Barry, May 02 2005
E.g.f.: exp(x)Bessel_I(1,2*I*x)/I, I=sqrt(1);  Paul Barry, Feb 10 2006


PROG

(PARI) {a(n)=polcoeff(((1x)/sqrt(12*x+5*x^2+x^2*O(x^n))1)/(2*x), n)}


CROSSREFS

Cf. A104505, A007440, A104507, A104508, A104509.
Sequence in context: A009524 A009794 A171402 * A088138 A186033 A120559
Adjacent sequences: A104503 A104504 A104505 * A104507 A104508 A104509


KEYWORD

sign


AUTHOR

Paul D. Hanna, Mar 11 2005


STATUS

approved



