A081766 Numbers k such that k^2+1 divides C(2k,k).

0, 1, 3, 8, 13, 17, 30, 46, 47, 68, 73, 75, 93, 98, 105, 112, 122, 144, 155, 172, 183, 189, 192, 203, 217, 233, 237, 242, 254, 266, 268, 269, 278, 286, 294, 348, 380, 401, 403, 411, 423, 437, 439, 443, 456, 463, 476, 483, 489, 494, 498, 511, 520, 526, 540, 563

Offset: 1

Author

Benoit Cloitre, Apr 09 2003

Keywords

• easy
• nonn

Links

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

Crossrefs

Cf. A000984, A002522.

Programs

Mathematica

Select[Range[0, 600], Divisible[Binomial[2*#, #], #^2 + 1] &] (* Amiram Eldar, May 08 2022 *)

Extensions

a(1) = 0 inserted by Amiram Eldar, May 08 2022