A343225 Primitive terms of A343218. Numbers k such that A343220(k) = 1.

3, 7, 10, 11, 17, 19, 20, 23, 26, 27, 29, 31, 32, 40, 43, 45, 47, 52, 53, 59, 65, 67, 71, 72, 74, 79, 80, 82, 83, 89, 98, 103, 104, 107, 117, 122, 125, 127, 128, 131, 139, 146, 148, 149, 151, 162, 163, 164, 167, 179, 185, 191, 194, 196, 197, 199, 200, 202, 205, 208, 211, 218, 223, 226, 227, 233, 239, 243, 244, 245, 251

Offset: 1

Author

Antti Karttunen, Apr 09 2021

Keywords

• nonn

Comments

For any term x, and for any y > 0, if gcd(x,y) = 1, then x*y is included in A343218.

Crossrefs

Positions of 1's in A343220.

Subsequence of A343218.

Cf. A000203, A003415, A343219.

Programs

PARI

A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A343219(n) = (A003415(sigma(n))>n);
A343220(n) = sumdiv(n,d,if(1==gcd(d,n/d),A343219(d),0));
isA343225(n) = (1==A343220(n));