OFFSET
1,2
COMMENTS
n*omega(n)/phi(n) appears in certain bounds of Erdős for the Jacobsthal function g(n) (A048669).
REFERENCES
József Sándor, Dragoslav S. Mitrinovic, and Borislav Crstici, Handbook of Number Theory I, Springer Science & Business Media, 2005, Chapter I, p. 34, section I.32.3.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Paul Erdős, On the integers relatively prime to n and on a number theoretic function considered by Jacobsthal, Math. Scand., 10, 1962, 163-170.
MAPLE
MATHEMATICA
Round[Table[(n PrimeNu[n] + 1/2)/EulerPhi[n], {n, 1, 100}]] (* Vincenzo Librandi, Apr 21 2017 - confirmed by Giovanni Resta *)
PROG
(Magma) [Round(n*#PrimeDivisors(n)/EulerPhi(n)): n in [1..100]] // Vincenzo Librandi, Apr 21 2017
(PARI) a(n) = {my(f = factor(n)); round(n*omega(f)/eulerphi(f)); } \\ Amiram Eldar, Apr 25 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Apr 19 2017
STATUS
approved