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A110129 Central coefficients of a scaled Legendre triangle. 2
1, 2, 22, 504, 16966, 752800, 41492284, 2734083968, 209681631814, 18348172005888, 1804161160185748, 196945525458761728, 23633625832975567644, 3092337510752711057408, 438161926888980929318584 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Central coefficients of triangle A110124.

LINKS

Table of n, a(n) for n=0..14.

FORMULA

a(n)=2^n*LegendreP(n, n); a(n)=sum{j=0..floor(n/2), (-1)^j*C(n, j)C(2n-2j, n)n^(n-2j).

MATHEMATICA

Table[2^n LegendreP[n, n], {n, 0, 20}] (* Harvey P. Dale, Nov 28 2012 *)

PROG

(PARI) a(n)=pollegendre(n, n)<<n \\ Charles R Greathouse IV, Mar 19 2017

CROSSREFS

Sequence in context: A137076 A090730 A090313 * A328020 A246740 A248798

Adjacent sequences:  A110126 A110127 A110128 * A110130 A110131 A110132

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Jul 13 2005

STATUS

approved

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Last modified August 8 02:21 EDT 2020. Contains 336290 sequences. (Running on oeis4.)