A060474 a(n) = denominator of phi(n)/(n+1), where phi(n) is Euler's phi, A000010.

2, 3, 2, 5, 3, 7, 4, 9, 5, 11, 6, 13, 7, 5, 2, 17, 9, 19, 10, 21, 11, 23, 12, 25, 13, 9, 14, 29, 15, 31, 16, 33, 17, 35, 3, 37, 19, 13, 5, 41, 21, 43, 22, 9, 23, 47, 24, 49, 25, 51, 13, 53, 27, 55, 7, 19, 29, 59, 30, 61, 31, 21, 16, 65, 11, 67, 34, 69, 35, 71, 36, 73, 37, 25, 19, 77, 13, 79, 40

Offset: 1

Author

Fabian Rothelius, Mar 16 2001

Keywords

• easy
• frac
• nice
• nonn

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000010, A060473.

Programs

Maple

with(numtheory,phi): seq(denom(phi(n)/(n+1)), n=1..50);

Mathematica

Denominator[Table[EulerPhi[n]/(n+1),{n,80}]] (* Harvey P. Dale, Apr 13 2012 *)

PARI

{ for (n=1, 1000, write("b060474.txt", n, " ", denominator(eulerphi(n)/(n + 1))); ) } \\ Harry J. Smith, Jul 13 2009

Python

from sympy import totient, gcd
def A060474(n): return (n+1)//gcd(n+1,totient(n)) # Chai Wah Wu, Apr 02 2021

Extensions

More terms from Asher Auel, Mar 16 2001

A Maple program that should have been a PARI program removed by Harry J. Smith, Jul 13 2009