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A163378
a(n) = sigma(phi(tau(n))).
3
1, 1, 1, 3, 1, 3, 1, 3, 3, 3, 1, 3, 1, 3, 3, 7, 1, 3, 1, 3, 3, 3, 1, 7, 3, 3, 3, 3, 1, 7, 1, 3, 3, 3, 3, 12, 1, 3, 3, 7, 1, 7, 1, 3, 3, 3, 1, 7, 3, 3, 3, 3, 1, 7, 3, 7, 3, 3, 1, 7, 1, 3, 3, 12, 3, 7, 1, 3, 3, 7, 1, 7, 1, 3, 3, 3, 3, 7, 1, 7, 7, 3, 1, 7, 3, 3
OFFSET
1,4
LINKS
FORMULA
MATHEMATICA
Table[DivisorSigma[1, EulerPhi[DivisorSigma[0, n]]], {n, 100}] (* Harvey P. Dale, Jun 21 2016 *)
PROG
(PARI) vector(100, n, sigma(eulerphi(numdiv(n)))) \\ G. C. Greubel, Dec 20 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Jul 25 2009
EXTENSIONS
More terms from Harvey P. Dale, Jun 21 2016
STATUS
approved