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.

A336557 Numbers k such that A336456(n) = Product_{p^e|n} A336456(p^e). Here each p^e is the maximal power of prime p that divides k, and A336456(n) = A335915(sigma(sigma(n))).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 23, 24, 25, 26, 27, 28, 29, 31, 32, 36, 37, 38, 39, 41, 43, 44, 45, 47, 48, 49, 50, 51, 53, 54, 56, 59, 60, 61, 62, 63, 64, 67, 68, 71, 72, 73, 74, 75, 76, 78, 79, 80, 81, 83, 86, 87, 89, 92, 95, 96, 97, 99, 100, 101, 103, 104, 107, 108, 109, 111, 112
Offset: 1

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Author

Antti Karttunen, Jul 25 2020

Keywords

Comments

Numbers at which points A336456 appears to be multiplicative.

Crossrefs

Cf. A336556 (characteristic function), A336558 (complement).
Union of A000961 and A336559.
Union of A336547 and A336560.