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Numbers n with property that binomial (2n, n) / (n-2) is an integer.
2

%I #2 Mar 30 2012 17:31:01

%S 3,4,5,6,8,14,17,20,22,26,30,42,44,47,68,74,79,86,90,93,101,106,112,

%T 122,128,142,155,158,172,189,192,200,206,211,212,218,222,230,233,240,

%U 242,268,275,278,301,306,310,314,317,324,327,332,338,344,347,370,380,416

%N Numbers n with property that binomial (2n, n) / (n-2) is an integer.

%t Select[ Range[421], Mod[Binomial[2#, # ], (# - 2)] == 0 &]

%Y Cf. A000108, A094453, A094575.

%K nonn

%O 1,1

%A _Robert G. Wilson v_, May 11 2004