A066159 Numbers k such that 4k-1 divides (2k-1)! + 1.

2, 3, 5, 11, 12, 17, 20, 26, 32, 33, 41, 45, 48, 50, 57, 66, 87, 92, 96, 105, 108, 111, 120, 123, 126, 131, 141, 143, 150, 152, 155, 158, 171, 173, 182, 185, 186, 197, 206, 210, 216, 222, 237, 248, 255, 263, 272, 273, 281, 288, 297, 323, 330, 342

Offset

1,1

Links

Harry J. Smith, Table of n, a(n) for n=1..1000

Ed Pegg, Jr., Math. Puzzles (Material added Dec 11 2001)

Maple

A066159:=n->`if`((2*n-1)!+1 mod (4*n-1) = 0, n, NULL): seq(A066159(n), n=1..500); # Wesley Ivan Hurt, Dec 01 2015

Mathematica

Select[Range@ 360, Divisible[(2 # - 1)! + 1, 4 # - 1] &] (* Michael De Vlieger, Dec 02 2015 *)

Prog

(PARI) isok(k) = { ((2*k - 1)! + 1) % (4*k - 1) == 0 } \\ Harry J. Smith, Feb 03 2010

Crossrefs

Cf. A066160.

Sequence in context: A354400 A210144 A243357 * A316794 A372009 A103027

Adjacent sequences: A066156 A066157 A066158 * A066160 A066161 A066162

Keyword

nonn

Author

N. J. A. Sloane, Dec 13 2001

Extensions

Reference into the Math Puzzles made more specific by R. J. Mathar, Feb 11 2010

Status

approved