A073077 Numbers k that divide C(2k,k) and C(4k,2k).

1, 2, 20, 110, 156, 210, 220, 238, 240, 312, 460, 468, 483, 510, 561, 600, 624, 665, 684, 696, 720, 744, 770, 806, 812, 816, 868, 936, 966, 1001, 1012, 1045, 1064, 1100, 1110, 1122, 1144, 1155, 1170, 1200, 1295, 1309, 1320, 1326, 1332, 1360, 1368, 1394, 1404

Offset

1,2

Links

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

Mathematica

Select[Range[1500], Divisible[Binomial[2*#, #], #] && Divisible[Binomial[4*#, 2*#], #] &] (* Amiram Eldar, Apr 26 2025 *)

Prog

(PARI) isok(n) = !(binomial(2*n, n) % n) && !(binomial(4*n, 2*n) % n); \\ Michel Marcus, Nov 28 2013

Crossrefs

Subsequence of A014847.

Cf. A000984, A001448.

Sequence in context: A052361 A001884 A028477 * A069537 A282818 A001797

Adjacent sequences: A073074 A073075 A073076 * A073078 A073079 A073080

Keyword

easy,nonn

Author

Benoit Cloitre, Aug 17 2002

Extensions

More terms from Michel Marcus, Nov 28 2013

Status

approved