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A295302
a(n) = sigma(phi(n)) - n, where phi = A000010 and sigma = A000203.
3
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
1,5
LINKS
FORMULA
a(n) = A062402(n) - n.
MATHEMATICA
Table[DivisorSigma[1, EulerPhi[n]]-n, {n, 90}] (* Harvey P. Dale, Mar 27 2019 *)
PROG
(PARI) A295302(n) = (sigma(eulerphi(n)) - n);
CROSSREFS
Cf. A018784 (positions of zeros), A230201 (of negative terms), A230203 (of positive terms).
Sequence in context: A123962 A256888 A010585 * A110879 A016587 A123217
KEYWORD
sign
AUTHOR
Antti Karttunen, Nov 21 2017
STATUS
approved