A374138 Numbers k that have more than two prime factors (with multiplicity) and A075255(k) is a multiple of A374127(k).

8, 28, 496, 8128, 627013, 3713337, 33550336, 64488069, 3919528877

Offset

1,1

Links

Table of n, a(n) for n=1..9.

Index entries for sequences where odd perfect numbers must occur, if they exist at all

Formula

{k | A001222(k) > 2 and gcd(A075255(k), A374127(k)) = abs(A374127(k))}.

Prog

(PARI)
A001414(n) = ((n=factor(n))[, 1]~*n[, 2]);
A374128(n) = { my(s=A001414(n), x=n-s, u=(sigma(n)-s)-n); (gcd(x, u)==abs(u)); };
isA374138(n) = ((bigomega(n) > 2) && A374128(n));

Crossrefs

Intersection of A033942 and A374129.

Cf. A000203, A001222, A001414, A075255, A374127.

Cf. A000396 (after its initial 6, is a subsequence).

Sequence in context: A244613 A228281 A146977 * A068623 A361585 A297885

Adjacent sequences: A374135 A374136 A374137 * A374139 A374140 A374141

Keyword

nonn,hard,more

Author

Antti Karttunen, Jul 06 2024

Status

approved