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A004529 Ratios of successive terms are 1,1,1,2,3,3,3,4,5,5,5,6,... 2
1, 1, 1, 1, 2, 6, 18, 54, 216, 1080, 5400, 27000, 162000, 1134000, 7938000, 55566000, 444528000, 4000752000, 36006768000, 324060912000, 3240609120000, 35646700320000, 392113703520000, 4313250738720000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Robert Israel, Table of n, a(n) for n = 0..506

FORMULA

a(n) = Product_{j=0..n-1} (A180969(2,j+1) + A180969(2,j) + 1) = a(n-1) * (A180969(2,n-1) + A180969(2,n-2) + 1). - Adriano Caroli, Nov 27 2010

a(4*k+j) = 16^k * k! * Gamma(k+1/2)^3*(2*k+1)^j/Gamma(1/2)^3 for 0 <= j <= 3. - Robert Israel, Jun 19 2018

MAPLE

seq(seq(16^k * k! * GAMMA(k+1/2)^3*(2*k+1)^j/GAMMA(1/2)^3, j=0..3), k=0..10); # Robert Israel, Jun 19 2018

CROSSREFS

Sequence in context: A275872 A148455 A094590 * A238236 A294159 A000778

Adjacent sequences:  A004526 A004527 A004528 * A004530 A004531 A004532

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified October 19 22:28 EDT 2018. Contains 316378 sequences. (Running on oeis4.)