A065349 Positions of zeros in A065346.

19, 41, 42, 43, 49, 50, 53, 54, 55, 58, 67, 71, 74, 75, 95, 97, 98, 99, 102, 103, 123, 135, 138, 139, 145, 149, 153, 154, 155, 159, 163, 165, 166, 167, 168, 169, 170, 173, 174, 175, 178, 179, 180, 183, 184, 185, 191, 193, 194, 195, 197, 198, 199, 200, 201, 202

Offset: 1

Author

Labos Elemer, Oct 30 2001

Keywords

• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000
• C. Pomerance, Divisors of the middle binomial coefficient, Amer. Math. Monthly, 112 (2015), 636-644.

Crossrefs

Cf. A000108, A065344, A065345, A065346, A065347, A065348.

Programs

Mathematica

ris = {}; Do[If[Mod[Binomial[2 n, n], (n + 1) (n + 2) (n + 3) (n + 4)] == 0, AppendTo[ris, n]], {n, 250}]; ris (* Bruno Berselli, Jan 06 2014 *)

PARI

isok(k) = { binomial(2*k, k) % ((k + 1)*(k + 2)*(k + 3)*(k + 4)) == 0 } \\ Harry J. Smith, Oct 17 2009