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.

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A373739 a(n) is the smallest number that is in a cycle of length n when iterating x <- phi(sigma(x)).

Original entry on oeis.org

1, 4, 16, 576
Offset: 1

Views

Author

Jud McCranie, Jun 15 2024

Keywords

Comments

Terms in a cycle are distinct, i.e., going twice around a cycle of length 3 is not considered a cycle of length 6.
Other terms: a(5) <= 339026688000000, a(6) = 1800, a(8) <= 12959170560000, a(9) = 113218560, a(11) = 326592, a(12) = 5033164800, a(15) = 40255488, a(18) <= 150493593600, a(21) = 12227604480, a(22) <= 1316603904000.

Examples

			16 -> 24 -> 30 -> 16, 16 is the smallest member of any cycle of length 3, so a(3)=16.

Crossrefs

Cf. A062401, A095955, A095956, A373435, A373453, A373454.

A375122 A cycle of length 5 when iterating x <- phi(sigma(x)).

Original entry on oeis.org

6634509269055173050761216000, 7521613519844726223667200000, 7946886558074859593662464000, 7794495412499746337587200000, 7970172471593905204651622400
Offset: 1

Views

Author

Jud McCranie, Jul 30 2024

Keywords

Comments

The first term is the smallest member of the cycle. Another cycle with length 5 is A375012.

Crossrefs

Cf. A095955, A095956, A001229, A373435, A373453, A373454, A375012, A375013, A375014.
Previous Showing 21-22 of 22 results.

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