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A061370 a(n) = floor(ratio of product and sum of first n numbers). 2
1, 0, 1, 2, 8, 34, 180, 1120, 8064, 65978, 604800, 6141046, 68428800, 830269440, 10897286400, 153844043294, 2324754432000, 37440781904842, 640237370572800, 11585247657984000, 221172909834240000, 4442690623626907826 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..100

FORMULA

a(n) = floor(2*(n-1)! / (n+1)).

EXAMPLE

a(6) = floor(720/21) = 34.

MAPLE

a:=n->floor(mul(j, j=1..n)/sum(j, j=1..n)):seq(a(n), n=1..23); # Zerinvary Lajos, Dec 07 2008

MATHEMATICA

Table[ Floor[2*(n - 1)!/(n + 1)], {n, 1, 24} ]

PROG

(PARI) { default(realprecision, 100); for (n=1, 100, if (n==1, f=2, f*=(n - 1)); write("b061370.txt", n, " ", f\(n + 1)) ) } \\ Harry J. Smith, Jul 22 2009

CROSSREFS

Sequence in context: A030871 A030960 A121894 * A126328 A268558 A191569

Adjacent sequences:  A061367 A061368 A061369 * A061371 A061372 A061373

KEYWORD

nonn,easy

AUTHOR

Amarnath Murthy, May 02 2001

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), May 07 2001

STATUS

approved

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Last modified August 3 02:48 EDT 2021. Contains 346435 sequences. (Running on oeis4.)