A295302 a(n) = sigma(phi(n)) - n, where phi = A000010 and sigma = A000203.

0, -1, 0, -1, 2, -3, 5, -1, 3, -3, 7, -5, 15, -2, 0, -1, 14, -6, 20, -5, 7, -4, 13, -9, 17, 2, 12, 0, 27, -15, 41, -1, 9, -3, 25, -8, 54, 1, 21, -9, 49, -14, 53, -2, 15, -10, 25, -17, 47, -8, 12, 8, 45, -15, 35, 4, 34, -2, 31, -29, 107, 10, 28, -1, 59, -24, 77, -5, 15, -10, 73, -12, 122, 17, 15, 15, 91, -18, 89, -17, 39, 8

Offset: 1

Author

Antti Karttunen, Nov 21 2017

Keywords

• sign

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537

Crossrefs

Cf. A000010, A000203, A062402, A295301, A295304.

Cf. A018784 (positions of zeros), A230201 (of negative terms), A230203 (of positive terms).

Programs

Mathematica

Table[DivisorSigma[1,EulerPhi[n]]-n,{n,90}] (* Harvey P. Dale, Mar 27 2019 *)

PARI

A295302(n) = (sigma(eulerphi(n)) - n);

Formula

a(n) = A062402(n) - n.