A080170 - OEIS

A080170

Numbers k such that gcd(C(2*k,k), C(3*k,k), C(4*k,k), ..., C((k+1)*k,k) ) = 1.

29, 59, 69, 83, 89, 104, 119, 125, 131, 139, 153, 164, 167, 179, 181, 194, 197, 209, 219, 230, 233, 251, 259, 263, 272, 279, 285, 305, 307, 311, 314, 329, 335, 339, 356, 359, 363, 373, 379, 384, 389, 395, 398, 407, 417, 419, 428, 439, 441, 454, 455, 461

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

a(n) = A051283(n) - 1 (conjectured). - Ralf Stephan, Feb 20 2004

LINKS

Table of n, a(n) for n=1..52.

MATHEMATICA

Select[Range[500], GCD@@Table[Binomial[k*#, # ], {k, 2, #+1}]==1&]

PROG

(Haskell)

a080170 n = a080170_list !! (n-1)