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.

A368903 Numbers k for which there is no prime p such that p^p divides A342001(k), but for A003415(k) such a prime exists. Here A003415(n) is the arithmetic derivative of n, and A342001(n) = A003415(n) / A003557(n).

Original entry on oeis.org

4, 8, 24, 27, 32, 36, 40, 48, 54, 56, 60, 64, 72, 80, 84, 88, 96, 100, 104, 112, 120, 128, 132, 135, 136, 140, 152, 156, 162, 168, 176, 184, 196, 200, 204, 216, 220, 224, 228, 232, 243, 248, 260, 264, 270, 272, 276, 280, 288, 296, 304, 308, 312, 324, 328, 340, 344, 348, 351, 352, 360, 364, 368, 372, 376, 378, 380
Offset: 1

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Author

Antti Karttunen, Jan 09 2024

Keywords

Comments

Numbers k such that A342001(k) is in A048103, but A003415(k) is in its complement A100716. The condition implies that k itself is in A100716.
The converse case, where p^p divides A342001(k) but not A003415(k), is not possible because the former is a divisor of the latter.

Examples

			For n = 27 = 3^3, A003415(27) = 27, and A342001(27) = 3, thus as 3^3 divides the former, but not the latter, 27 is included in this sequence.
		

Crossrefs

Setwise difference A368904 \ A358215. Subsequence of A100716.
Cf. A368913 (characteristic function).

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