A056100 Sigma(n)*Phi(n) + 1 (Mod n).

0, 0, 0, 3, 0, 1, 0, 5, 7, 3, 0, 5, 0, 5, 13, 9, 0, 1, 0, 17, 7, 9, 0, 1, 21, 11, 19, 1, 0, 7, 0, 17, 4, 15, 33, 13, 0, 17, 19, 1, 0, 19, 0, 9, 28, 21, 0, 17, 43, 11, 10, 13, 0, 1, 21, 25, 31, 27, 0, 49, 0, 29, 28, 33, 3, 43, 0, 21, 16, 27, 0, 1, 0, 35, 11, 25, 63, 55, 0, 33, 55, 39, 0, 1

Offset

1,4

References

George E. Andrews, "Number Theory," Dover Publ., NY, 1971, page 85.

Links

Table of n, a(n) for n=1..84.

Mathematica

Do[Print[Mod[DivisorSigma[1, n]*EulerPhi[n] + 1, n]], {n, 1, 100}] Note that iff n is a prime then Sigma(n)*Phi(n) + 1 = 0 (Mod n).

Crossrefs

Sequence in context: A046665 A100574 A342122 * A141665 A136689 A359364

Adjacent sequences: A056097 A056098 A056099 * A056101 A056102 A056103

Keyword

easy,nonn

Author

Robert G. Wilson v, Jul 28 2000

Status

approved