A069061 Sum of divisors of 2^n+1.

4, 6, 13, 18, 48, 84, 176, 258, 800, 1302, 2736, 4356, 10928, 20520, 51792, 65538, 174768, 351120, 699056, 1110276, 3100240, 5048232, 11184816, 17041416, 49012992, 82623888, 211053040, 284225796, 727960800, 1494039792, 2863311536, 4301668356, 12611914848, 20788904016

Offset

1,1

Links

Max Alekseyev, Table of n, a(n) for n = 1..1122 (terms 1..1062 from Amiram Eldar)

Formula

a(n) = sigma(2^n+1).

a(n) = A000203(A000051(n)). - Michel Marcus, Nov 24 2013

Prog

(PARI) a(n) = sigma(2^n+1); \\ Michel Marcus, Nov 24 2013

Crossrefs

Cf. A000051, A000203, A002185, A002587, A002589, A046798, A046799, A053285, A054992, A057957, A059886, A085029, A086257, A112092, A250291, A274906, A295501.

Sequence in context: A191198 A191137 A247284 * A088811 A007977 A013122

Adjacent sequences: A069058 A069059 A069060 * A069062 A069063 A069064

Keyword

nonn

Author

Benoit Cloitre, Apr 04 2002

Extensions

More terms from Amiram Eldar, Oct 04 2019

Status

approved