A351552 Numbers k for which A351546(k) divides k, where A351546(n) is the largest unitary divisor of sigma(n) such that none of its prime factors divide A003961(n).

1, 2, 10, 20, 24, 34, 40, 106, 120, 160, 216, 224, 260, 340, 408, 440, 480, 520, 580, 672, 680, 696, 792, 820, 1060, 1120, 1272, 1392, 1450, 1640, 1666, 1760, 1780, 1940, 2080, 2120, 2136, 2320, 2340, 2464, 2720, 2900, 3040, 3320, 3332, 3576, 3680, 3808, 3880, 3960, 4280, 4320, 4536, 4640, 4680, 5280, 5380, 5800, 5860

Offset: 1

Author

Antti Karttunen, Feb 16 2022

Keywords

• nonn

Comments

See comments in A351551.

Links

• Index entries for sequences related to primorial base
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A000203, A003961, A351546.

Not a subsequence of A351554.

Cf. A351551 (subsequence).

Programs

PARI

A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A351546(n) = { my(f=factor(sigma(n)),u=A003961(n)); prod(k=1,#f~,f[k,1]^((0!=(u%f[k,1]))*f[k,2])); };
isA351552(n) = !(n%A351546(n));