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 1-2 of 2 results.

A330413 Integers m such that sigma(m) + sigma(16*m) = 34*m.

Original entry on oeis.org

268, 4336, 69568, 73014378496, 18691696623616, 80280230208715249156096, 5516815412193254337299253840314368, 22596875928343569838211798520159010816, 106710729501573572985208420194451100911225778218295042768896, 7689318425915528602346510723233181380859942271270135051778769275060995751936
Offset: 1

Views

Author

Jinyuan Wang, Feb 12 2020

Keywords

Comments

This is the case h = 16 of the h-perfect numbers as defined in the Harborth link.

Examples

			268 is a term since sigma(268) + sigma(16*268) = 9112, that is 34*268.

Links

Crossrefs

Cf. A000203, A000396, A001774, A136539, A281993, A330412.

Programs

  • PARI
    isok(m) = sigma(m) + sigma(16*m) == 34*m;

Formula

a(n) = 2^A001774(n) * (17*2^A001774(n) - 1).

A334128 Integers m such that sigma(m) + sigma(7*m) = 16*m.

Original entry on oeis.org

135, 1365, 42819777
Offset: 1

Views

Author

Jinyuan Wang, May 15 2020

Keywords

Comments

This is the case h = 7 of the h-perfect numbers as defined in the Harborth link.
If gcd(m, 7) = 1 and m is even, then m must be of the form 2*q, where 27*sigma(q) = 32*q and gcd(q, 7) = 1.
a(4) > 3.5*10^12, if it exists. - Giovanni Resta, May 17 2020

Links

Crossrefs

Cf. A000203, A000396, A281993, A330412, A330413.

Programs

  • PARI
    isok(m) = sigma(m) + sigma(7*m) == 16*m;
Showing 1-2 of 2 results.

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

Content is available under The OEIS End-User License Agreement.