A004783 Numbers k such that 3!*(2k-4)!/(k!*(k-1)!) is an integer.

2, 3, 4, 7, 13, 16, 19, 21, 29, 43, 46, 67, 78, 85, 89, 92, 100, 105, 111, 121, 127, 141, 154, 157, 171, 188, 191, 199, 205, 210, 211, 217, 221, 229, 232, 239, 241, 267, 274, 277, 300, 309, 313, 316, 323, 326, 331, 343, 346, 369, 379, 415, 421, 430

Offset

1,1

Links

Table of n, a(n) for n=1..54.

Mathematica

Select[Range[500], IntegerQ[3! (2 # - 4)!/(#! (# - 1)!)] &] (* Arkadiusz Wesolowski, Sep 06 2011 *)

Crossrefs

Sequence in context: A022437 A057983 A200088 * A031149 A096723 A266498

Adjacent sequences: A004780 A004781 A004782 * A004784 A004785 A004786

Keyword

nonn

Author

R. K. Guy

Extensions

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

Status

approved