A067315 Numbers k such that binomial(k, floor(k/2)) is not divisible by k.

4, 6, 8, 10, 14, 16, 18, 20, 22, 24, 26, 28, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 86, 88, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 134, 136, 138, 140

Offset: 1

Author

Labos Elemer, Jan 14 2002

Keywords

• nonn

Comments

All the terms are even. - Amiram Eldar, Aug 24 2024

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A001405, A042970, A042996 (complement), A067348.

Programs

Mathematica

Select[ Range[ 2, 150, 2 ], Mod[ Binomial[ #, #/2 ], # ]>0& ]

PARI

is(k) = binomial(k, k\2) % k > 0; \\ Amiram Eldar, Aug 24 2024