A179280 - OEIS

A179280

E.g.f. equals the real part of the series F(x) = 1 + x*F(x)^i where i=sqrt(-1).

1, 1, 0, -9, 48, 350, -11160, 73010, 2607360, -84724380, 274118400, 58934005900, -1878039820800, -11920073789000, 2984939450438400, -86257610003799000, -2337484592701440000, 281472063119891306000, -6445251832278924288000

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,4

LINKS

Table of n, a(n) for n=0..18.

FORMULA

a(n) = real part of C(i*n,n)/(i*n-n+1).

EXAMPLE

E.g.f.: 1 + x - 9*x^3/3! + 48*x^4/4! + 350*x^5/5! - 11160*x^6/6! + ...

E.g.f. equals the real part of F(x) = 1 + x*F(x)^i where

F(x) = 1 + x + i*x^2 - (3 + i)*x^3/2 + (6 - 7*i)*x^4/3 + (35 + 72*i)*x^5/12 - (31 - i)*x^6/2 + (1043 - 2511*i)*x^7/72 + (4074 + 4393*i)*x^8/63 - (52299 - 17108*i)*x^9/224 + (171324 - 1458013*i)*x^10/2268 + (53576369 + 32934483*i)*x^11/36288 - (1811381 - 1198743*i)*x^12/462 + ...

PROG

(PARI) {a(n)=n!*real(binomial(I*n, n)/((I-1)*n+1))}

CROSSREFS

Cf. A179281 (imaginary part).

Sequence in context: A226751 A073584 A007037 * A293095 A283092 A249780

Adjacent sequences: A179277 A179278 A179279 * A179281 A179282 A179283

KEYWORD

sign

AUTHOR

Paul D. Hanna, Jul 08 2010

STATUS

approved