A079463 Numbers k such that C(6*k,n)/(5*k+1) (A002295) is not divisible by 6.

0, 1, 3, 4, 5, 7, 13, 16, 19, 21, 22, 34, 40, 49, 51, 53, 67, 77, 83, 85, 97, 103, 115, 121, 148, 196, 202, 205, 211, 213, 292, 307, 309, 310, 333, 339, 340, 341, 346, 358, 364, 439, 445, 583, 589, 601, 607, 819, 821, 845, 851, 853, 877, 925, 931, 1021, 1039, 1069

Offset: 1

Author

Benoit Cloitre, Jan 14 2003

Keywords

• nonn

Comments

Is a(n)/n^2 bounded? It seems that 0.2 < a(n)/n^2 <= 1.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000225 (C(2*k, k)/(k+1) is not divisible by 2), A003462 (C(3*k, k)/(2*k+1) is not divisible by 3), A003463 (C(5*k, k)/(4*k+1) is not divisible by 5).

Programs

Mathematica

Select[Range[0,1000], !Divisible[Binomial[6*#,#]/(5*# + 1),6] &] (* Amiram Eldar, Jun 04 2021 *)