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A132464 Let df(n,k) = Product_{i=0..k-1} (n-i) be the descending factorial and let P(m,n) = df(n-1,m-1)^2*(2*n-m)/((m-1)!*m!). Sequence gives P(6,n). 1
0, 0, 0, 0, 0, 1, 48, 735, 6272, 37044, 169344, 640332, 2090880, 6073353, 16032016, 39078039, 89037312, 191456720, 391523328, 766192176, 1442244096, 2622518073, 4623197040, 7925786407, 13248326784, 21641442900, 34616067200, 54311107500, 83710972800 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..29.

Index entries for linear recurrences with constant coefficients, signature (12, -66, 220, -495, 792, -924, 792, -495, 220, -66, 12, -1).

FORMULA

From Robert Israel, Jul 16 2020: (Start)

a(n) = (n - 5)^2*(n - 4)^2*(n - 3)^2*(n - 2)^2*(n - 1)^2*(2*n - 6)/86400.

G.f.: (1 + 36*x + 225*x^2 + 400*x^3 + 225*x^4 + 36*x^5 + x^6)*x^6/(1 - x)^12. (End)

MAPLE

seq((n - 5)^2*(n - 4)^2*(n - 3)^2*(n - 2)^2*(n - 1)^2*(2*n - 6)/86400, n=1..50); # Robert Israel, Jul 16 2020

CROSSREFS

See A132458 for further information.

Sequence in context: A138411 A186162 A102279 * A145155 A105948 A192839

Adjacent sequences:  A132461 A132462 A132463 * A132465 A132466 A132467

KEYWORD

nonn

AUTHOR

Ottavio D'Antona (dantona(AT)dico.unimi.it), Oct 31 2007

STATUS

approved

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Last modified September 19 05:33 EDT 2020. Contains 337176 sequences. (Running on oeis4.)