A379491 -id:A379491 - cp's OEIS frontend

A379486 Numbers k for which gcd(k,A003961(k))gcd(sigma(k),A276086(k)) is 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.

1, 2, 4, 6, 14, 16, 18, 24, 26, 28, 40, 54, 62, 64, 66, 74, 86, 102, 114, 122, 134, 138, 146, 152, 162, 169, 174, 176, 182, 184, 186, 206, 222, 234, 254, 270, 280, 282, 289, 290, 302, 304, 306, 308, 314, 318, 326, 338, 342, 354, 360, 361, 366, 368, 380, 384, 386, 402, 414, 422, 426, 434, 438, 441, 446, 448, 456, 474, 496

Offset: 1

Antti Karttunen, Jan 01 2025

nonn

Cf. A000203, A003961, A276086, A322361, A324198, A324644, A342671, A379485 (characteristic function), A379487, A379488.
Positions of 0's in A379489.
Cf. A379491 (subsequence, terms that are multiperfect numbers, A007691).

PARI
```
is_A379486 = A379485;
```

{Numbers k such that A379487(k) = A379488(k)}.

{Numbers k such that A322361(k)/A324198(k) = A324644(k)/A342671(k)}.

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.

Original entry on oeis.org

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

Offset: 1

Antti Karttunen, Jan 02 2025

nonn

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.

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

cp's OEIS Frontend

A379486 Numbers k for which gcd(k,A003961(k))gcd(sigma(k),A276086(k)) is 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.

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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.

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PARI

cp's OEIS Frontend

A379486 Numbers k for which gcd(k,A003961(k))*gcd(sigma(k),A276086(k)) is 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.

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PARI

Formula

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.

Views

Author

Keywords

Links

Crossrefs

Programs

PARI

A379486 Numbers k for which gcd(k,A003961(k))gcd(sigma(k),A276086(k)) is 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.

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.