A121823 (3^p+p)/(p+1) with (p + 1) odd prime > 3.

17, 105, 5369, 40881, 2532161, 20390553, 1364393897, 788854912241, 6641649422409, 4056611764783761, 296528425830656801, 2544627654221217657, 188573151481968108425, 121907205457107043376081, 79832689783834658219010233, 694937020905183664168761201, 461241110188546453162994653785, 35255711337932980300219323747689

Offset

1,1

Comments

See comments in A057900.

Links

Robert Israel, Table of n, a(n) for n = 1..315

Example

a(1) = (3^4 + 4)/(4+1) = 17, a(2) = (3^6 + 6)/(6+1) = 105.

Maple

map(t -> (3^(t-1)+t-1)/t, select(isprime, [seq(i, i=5..100, 2)])); # Robert Israel, Nov 13 2017

Crossrefs

Cf. A057900.

Sequence in context: A194475 A164745 A221938 * A268263 A343706 A282323

Adjacent sequences: A121820 A121821 A121822 * A121824 A121825 A121826

Keyword

nonn

Author

Zak Seidov, Aug 27 2006

Extensions

Corrected and edited according to suggestion of Michel Marcus by Zak Seidov, Oct 20 2013

More terms from Robert Israel, Nov 13 2017

Status

approved