A082377 Numbers k such that rad(k) - phi(k) <= 1, where rad = A007947 and phi = A000010.

1, 2, 3, 4, 5, 7, 8, 9, 11, 13, 16, 17, 18, 19, 23, 24, 25, 27, 29, 31, 32, 36, 37, 40, 41, 43, 45, 47, 48, 49, 50, 53, 54, 56, 59, 61, 63, 64, 67, 71, 72, 73, 75, 79, 80, 81, 83, 88, 89, 96, 97, 98, 99, 100, 101, 103, 104, 107, 108, 109, 112, 113, 117, 120, 121, 125, 127

Offset: 1

Author

Reinhard Zumkeller, Apr 10 2003

Keywords

• nonn

Comments

Includes all the prime numbers. - Amiram Eldar, Dec 05 2024

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000010 (phi), A007947 (rad).

Programs

PARI

is(n)=my(f=factor(n)[,1],r=prod(i=1,#f,f[i])); r-n/r*prod(i=1,#f,f[i]-1)<=1 \\ Charles R Greathouse IV, Feb 21 2013