A379492 Multiperfect numbers k for which gcd(k,A003961(k))*gcd(sigma(k),A276086(k)) is not equal to gcd(k,A276086(k))*gcd(sigma(k),A003961(k)), where A003961(n) is fully multiplicative with a(prime(i)) = prime(i+1), and A276086 is the primorial base exp-function.

120, 672, 523776, 1476304896, 14182439040, 31998395520, 518666803200, 13661860101120, 30823866178560, 740344994887680, 796928461056000, 212517062615531520, 69357059049509038080, 87934476737668055040, 154345556085770649600, 170206605192656148480, 1161492388333469337600, 1802582780370364661760, 9186050031556349952000

Offset: 1

Author

Antti Karttunen, Jan 02 2025

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..607
• Index entries for sequences where odd perfect numbers must occur, if they exist at all.
• Index entries for sequences related to prime indices in the factorization of n.
• Index entries for sequences related to primorial base.
• Index entries for sequences related to sigma(n).

Crossrefs

Intersection of A007691 and A000027\A379486.

Cf. A000203, A003961, A276086, A322361, A324198, A324644, A342671, A379485, A379487, A379488, A379491 (complement in A007691).

Cf. A046061 (seems to be a subsequence), A323653.

Programs

PARI

isA379492(n) = (!(sigma(n)%n) && !A379485(n));