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.

A370128 Numbers k such that (A276086(k)/s)^s >= k^(s-1) and A276086(k) <= A003415(k), where A003415 is the arithmetic derivative, A276086 is the primorial base exp-function, and s = bigomega(k).

Original entry on oeis.org

6, 213, 214, 2315, 2317, 2319, 2342, 2343, 2348, 2349, 2372, 2523, 2524, 2526, 2552, 4622, 4623, 4628, 4652, 6932, 6936, 6960, 30041, 30043, 30046, 30052, 30054, 30062, 30074, 30075, 30076, 30093, 30094, 30098, 30100, 30102, 30150, 30242, 30245, 30249, 30254, 30256, 30258, 30273, 30274, 30282, 32343, 32345, 32347
Offset: 1

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Author

Antti Karttunen, Feb 22 2024

Keywords

Comments

Numbers k such that A003415(k) >= A276086(k) >= s * k^((s-1)/s), with s = A001222(k).
See comments in A370127.

Crossrefs

Setwise difference A351228 \ A370127.

Programs

  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    isA370128(n) = { my(x=A276086(n), s=bigomega(n)); ((x<=A003415(n)) && ((x/s)^s >= n^(s-1))); };