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A004784 4!(2n-5)!/n!(n-1)! is an integer. 0
3, 4, 5, 211, 461, 562, 947, 990, 991, 1223, 1378, 1458, 1600, 1892, 2015, 2069, 2147, 2185, 2333, 2480, 2481, 2666, 2994, 3011, 3017, 3356, 3418, 3433, 3442, 3478, 3479, 3485, 3521, 3554, 3566, 3571, 3620, 3628, 3725, 3809, 3997, 4090, 4096 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..43.

MATHEMATICA

Select[Range[16^3], IntegerQ[4! (2 # - 5)!/(#! (# - 1)!)] &] (* Arkadiusz Wesolowski, Sep 06 2011 *)

CROSSREFS

Sequence in context: A254865 A085841 A163483 * A321404 A024687 A072631

Adjacent sequences:  A004781 A004782 A004783 * A004785 A004786 A004787

KEYWORD

nonn

AUTHOR

R. K. Guy

EXTENSIONS

Offset corrected and 2 initial terms added by Arkadiusz Wesolowski, Sep 06 2011

STATUS

approved

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Last modified September 21 21:58 EDT 2019. Contains 327282 sequences. (Running on oeis4.)