A097011 Remainder of sigma(n) modulo 30.

1, 3, 4, 7, 6, 12, 8, 15, 13, 18, 12, 28, 14, 24, 24, 1, 18, 9, 20, 12, 2, 6, 24, 0, 1, 12, 10, 26, 0, 12, 2, 3, 18, 24, 18, 1, 8, 0, 26, 0, 12, 6, 14, 24, 18, 12, 18, 4, 27, 3, 12, 8, 24, 0, 12, 0, 20, 0, 0, 18, 2, 6, 14, 7, 24, 24, 8, 6, 6, 24, 12, 15, 14, 24, 4, 20, 6, 18, 20, 6, 1, 6

Offset: 1

Author

Labos Elemer, Aug 19 2004

Keywords

• nonn

Links

• Indranil Ghosh, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A084301, A084303, A000203, A097012, A097013, A097014, A097015.

Programs

Mathematica

Table[Mod[DivisorSigma[1, n], 30], {n, 120}] (* Michael De Vlieger, Jan 10 2017 *)

PARI

a(n) = sigma(n) % 30; \\ Michel Marcus, Dec 19 2013

Formula

a(n) = mod(A000203(n), 30).