A374138 - OEIS

%I #11 Jul 07 2024 13:42:01

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

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

%H <a href="/index/O#opnseqs">Index entries for sequences where odd perfect numbers must occur, if they exist at all</a>

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

%o (PARI)

%o A001414(n) = ((n=factor(n))[, 1]~*n[, 2]);

%o A374128(n) = { my(s=A001414(n), x=n-s, u=(sigma(n)-s)-n); (gcd(x, u)==abs(u)); };

%o isA374138(n) = ((bigomega(n) > 2) && A374128(n));

%Y Intersection of A033942 and A374129.

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

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

%K nonn,hard,more

%O 1,1

%A _Antti Karttunen_, Jul 06 2024