cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A379494 a(n) = 2*A276086(n) - A276086(A001065(n)), where A276086 is the primorial base exp-function, and A001065 is the sum of proper divisors of n.

Original entry on oeis.org

3, 4, 10, 12, 34, 5, 18, 20, 51, 75, 178, -175, 98, 105, 270, 300, 898, -500, 498, -375, 1410, 2175, 4498, 1215, 2495, 3525, 7450, 5625, 22498, -161, 26, 28, -66, -249, 202, -8680, 138, -915, -30, -1995, 1258, -4025, 698, 735, 2058, 1275, 6298, -9275, 3485, 4900, 9750, 14175, 31498, 8505, 17050, 25809, 50250, 78729
Offset: 1

Views

Author

Antti Karttunen, Jan 05 2025

Keywords

Links

Crossrefs

Cf. A001065, A276086, A379493.

Programs

  • PARI
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A379494(n) = (2*A276086(n) - A276086(sigma(n)-n));

Formula

a(n) = 2*A276086(n) - A379493(n).

A379495 a(n) = A019565(A001065(n)), where A019565 is the base-2 exp-function, and A001065 is the sum of proper divisors of n.

Original entry on oeis.org

1, 2, 2, 6, 2, 15, 2, 30, 5, 7, 2, 11, 2, 21, 14, 210, 2, 110, 2, 165, 42, 105, 2, 65, 15, 11, 70, 385, 2, 273, 2, 2310, 210, 55, 70, 4290, 2, 165, 22, 429, 2, 2145, 2, 91, 26, 231, 2, 595, 7, 546, 110, 1365, 2, 51, 22, 17, 330, 13, 2, 7735, 2, 39, 182, 30030, 66, 1785, 2, 3003, 462, 357, 2, 102102, 2, 91, 286, 17, 66
Offset: 1

Views

Author

Antti Karttunen, Jan 05 2025

Keywords

Links

Crossrefs

Cf. A001065, A019565, A379496, A379501.
Cf. also A379493.

Programs

  • PARI
    A019565(n) = { my(m=1, p=1); while(n>0, p = nextprime(1+p); if(n%2, m *= p); n >>= 1); (m); };
A379495(n) = A019565(sigma(n)-n);

A379498 a(n) = A276086(1+n) - A276086(A001065(n)), where A276086 is the primorial base exp-function, and A001065 is the sum of proper divisors of n.

Original entry on oeis.org

2, 4, 7, 12, 3, 5, 13, 20, 36, 75, 23, -175, 73, 105, 195, 300, 123, -500, 373, -375, 1035, 2175, 623, 1215, 1870, 3525, 5575, 5625, 5, -161, 19, 28, -87, -249, -15, -8680, 103, -915, -135, -1995, 173, -4025, 523, 735, 1533, 1275, 873, -9275, 2610, 4900, 7125, 14175, 4373, 8505, 12675, 25809, 37125, 78729, 47
Offset: 1

Views

Author

Antti Karttunen, Jan 05 2025

Keywords

Links

Crossrefs

Cf. A001065, A276086, A379493, A379494.
Cf. also A379496.

Programs

  • PARI
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A379498(n) = (A276086(1+n) - A276086(sigma(n)-n));

Formula

a(n) = A276086(1+n) - A379493(n).
For even n, a(n) = A379494(n).
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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