The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A331817

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A331817

a(n) = (n!)^2 * Sum_{k=0..n} (2*k)! / (2^k * (k!)^3 * (n - k)!).
(history; published version)

#16 by Charles R Greathouse IV at Thu Sep 08 08:46:25 EDT 2022

PROG

(MAGMAMagma) [(Factorial(n))^2*&+[Factorial(2*k)/(2^k*(Factorial(k))^3*Factorial(n-k)):k in [0..n]]:n in [0..18]]; // Marius A. Burtea, Jan 27 2020

Discussion

Thu Sep 08

08:46

OEIS Server: https://oeis.org/edit/global/2944

#15 by R. J. Mathar at Mon Feb 08 06:55:05 EST 2021

STATUS

editing

approved

#14 by R. J. Mathar at Mon Feb 08 06:55:03 EST 2021

FORMULA

D-finite with recurrence a(n + 2) = 2*(3 + 2*n)*a(n + 1) - 3*(n + 1)^2*a(n). - Robert Israel, Feb 17 2020

STATUS

approved

editing

#13 by Joerg Arndt at Tue Feb 18 01:21:04 EST 2020

STATUS

proposed

approved

#12 by Robert Israel at Mon Feb 17 23:03:38 EST 2020

STATUS

editing

proposed

#11 by Robert Israel at Mon Feb 17 23:03:26 EST 2020

LINKS

Robert Israel, <a href="/A331817/b331817.txt">Table of n, a(n) for n = 0..380</a>

FORMULA

a(n + 2) = 2*(3 + 2*n)*a(n + 1) - 3*(n + 1)^2*a(n). - Robert Israel, Feb 17 2020

MAPLE

f:= gfun:-rectoproc({a(n + 2) = 2*(3 + 2*n)*a(n + 1) - 3*(n + 1)^2*a(n), a(0)=1, a(1)=2}, a(n), remember):

map(f, [$0..30]); # Robert Israel, Feb 17 2020

STATUS

approved

editing

#10 by Vaclav Kotesovec at Tue Jan 28 03:49:29 EST 2020

STATUS

editing

approved

#9 by Vaclav Kotesovec at Tue Jan 28 03:49:25 EST 2020

FORMULA

a(n) ~ 3^(n + 1/2) * n^n / exp(n). - Vaclav Kotesovec, Jan 28 2020

STATUS

approved

editing

#8 by Alois P. Heinz at Mon Jan 27 21:49:57 EST 2020

STATUS

proposed

approved

#7 by Marius A. Burtea at Mon Jan 27 14:36:10 EST 2020

STATUS

editing

proposed