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.

A351099 Composite numbers k such that the maximal digit value in primorial base expansion of the arithmetic derivative of k is not larger than the maximal exponent in the prime factorization of k.

Original entry on oeis.org

4, 8, 9, 10, 12, 14, 15, 16, 24, 25, 28, 30, 32, 36, 40, 45, 48, 49, 50, 54, 56, 58, 62, 64, 68, 74, 81, 87, 96, 98, 99, 108, 112, 120, 125, 128, 136, 155, 156, 160, 161, 162, 184, 189, 192, 196, 198, 203, 204, 208, 209, 210, 212, 217, 220, 221, 224, 225, 236, 244, 246, 247, 250, 252, 256, 268, 270, 272, 280, 282, 288
Offset: 1

Views

Author

Antti Karttunen, Feb 03 2022

Keywords

Comments

Composite k such that A328390(k) <= A051903(k).
Composite k for which A051903(A327859(n)) <= A051903(k).

Crossrefs

Programs

  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A051903(n) = if((1==n),0,vecmax(factor(n)[, 2]));
    A328114(n) = { my(s=0, p=2); while(n, s = max(s, (n%p)); n = n\p; p = nextprime(1+p)); (s); };
    isA351099(n) = (n>1&&!isprime(n)&&(A328114(A003415(n)) <= A051903(n)));