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A104506 Column 1 of triangle A104505, which is equal to the right-hand side of the triangle A084610 of coefficients in (1+x-x^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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

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

FORMULA

G.f.: ( (1-x)/sqrt(1-2*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(n-k, 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(((1-x)/sqrt(1-2*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

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Last modified December 4 21:51 EST 2016. Contains 278755 sequences.