A014850 Numbers k that divide s(k), where s(1)=1, s(j)=3*s(j-1)+j.

1, 3, 39, 507, 6591, 12207, 85683, 158691, 255567, 285987, 1028703, 1113879, 2062983, 3322371, 3717831, 3820791, 13373139, 14480427, 26818779, 31089279, 43190823, 48331803, 49670283, 79992471, 89513931, 173850807, 188245551, 321984039, 348644127, 404160627, 561480699, 628313439, 645713679

Offset

1,2

Links

Table of n, a(n) for n=1..33.

Example

39 is in the sequence as A000340(39-1) = 3039416364764232180 is divisible by 39. - David A. Corneth, Aug 08 2021

Prog

(PARI) lista(nn) = my(s); for(k=1, nn, s=3*s+k; if(s%k==0, print1(k, ", "))); \\ Jinyuan Wang, Aug 08 2021
(PARI) is(n) = n%2==1 && lift(Mod(3, n)^(n + 1) - Mod(3, n)) == 0 \\ David A. Corneth, Aug 08 2021

Crossrefs

s(n) = A000340(n-1).

Sequence in context: A063035 A198970 A361539 * A341671 A328809 A327603

Adjacent sequences: A014847 A014848 A014849 * A014851 A014852 A014853

Keyword

nonn

Author

N. J. A. Sloane, Olivier Gérard

Extensions

a(7)-a(16) from Arkadiusz Wesolowski, Jul 03 2011

More terms from David A. Corneth, Aug 08 2021

Status

approved