A073816 a(n) = 2^sigma(n) mod n.

0, 0, 1, 0, 4, 4, 4, 0, 2, 4, 4, 4, 4, 8, 1, 0, 4, 8, 4, 4, 4, 20, 4, 16, 23, 12, 16, 4, 4, 16, 4, 0, 25, 30, 1, 20, 4, 26, 22, 24, 4, 22, 4, 16, 19, 18, 4, 16, 36, 42, 1, 4, 4, 46, 26, 8, 28, 6, 4, 16, 4, 2, 4, 0, 1, 16, 4, 64, 49, 36, 4, 8, 4, 64, 16, 44, 64, 40, 4, 64, 11, 64, 4, 4, 16

Offset

1,5

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

n=17: sigma(17) = 18, 2^18 = 262144, 262144 mod 17 = 4 = a(17).

Mathematica

Table[PowerMod[2, DivisorSigma[1, n], n], {n, 90}] (* Harvey P. Dale, Jun 23 2014 *)

Crossrefs

Cf. A000203, A015910.

Sequence in context: A241056 A212618 A066602 * A368820 A084452 A176101

Adjacent sequences: A073813 A073814 A073815 * A073817 A073818 A073819

Keyword

nonn

Author

Labos Elemer, Aug 16 2002

Status

approved