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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).
4
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
1,2
COMMENTS
See comments in A351551.
PROG
(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));
CROSSREFS
Not a subsequence of A351554.
Cf. A351551 (subsequence).
Sequence in context: A038103 A307254 A293725 * A305448 A177150 A165551
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 16 2022
STATUS
approved