login
A163372
a(n) = sigma(phi(sigma(n))).
3
1, 3, 3, 12, 3, 7, 7, 15, 28, 12, 7, 28, 12, 15, 15, 72, 12, 60, 15, 28, 31, 28, 15, 31, 72, 28, 31, 60, 15, 60, 31, 91, 31, 39, 31, 195, 39, 31, 60, 60, 28, 63, 42, 60, 60, 60, 31, 168, 91, 168, 60, 96, 39, 63, 60, 63, 63, 60, 31, 124, 72, 63, 124, 312, 60, 124
OFFSET
1,2
LINKS
FORMULA
MAPLE
with(numtheory): A163372:=n->sigma(phi(sigma(n))): seq(A163372(n), n=1..100); # Wesley Ivan Hurt, Oct 06 2017
MATHEMATICA
DivisorSigma[1, EulerPhi[DivisorSigma[1, Range[100]]]] (* G. C. Greubel, Dec 20 2016 *)
PROG
(PARI) vector(80, n, sigma(eulerphi(sigma(n)))) \\ Michel Marcus, Jul 31 2015
(Magma) [SumOfDivisors(EulerPhi(SumOfDivisors(n))): n in [1..80]]; // Vincenzo Librandi, Dec 20 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Jul 25 2009
EXTENSIONS
More terms from Michel Marcus, Jul 31 2015
STATUS
approved