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.

A375848 The maximum exponent in the prime factorization of the numbers whose maximum exponent in their prime factorization is an evil number (A374590).

Original entry on oeis.org

0, 3, 3, 3, 5, 3, 3, 3, 6, 3, 3, 5, 3, 3, 3, 3, 3, 3, 3, 5, 3, 3, 3, 6, 3, 3, 5, 3, 5, 3, 3, 3, 3, 3, 5, 3, 3, 3, 6, 3, 3, 3, 3, 5, 3, 3, 3, 3, 3, 3, 5, 3, 3, 6, 3, 3, 3, 5, 5, 3, 3, 3, 9, 3, 3, 3, 3, 5, 3, 3, 6, 3, 3, 3, 5, 3, 3, 3, 3, 5, 3, 3, 3, 3, 3, 6, 3, 3, 6, 5, 3, 3, 3, 3, 3, 3, 3, 5, 3, 3, 6, 3, 3, 3, 5
Offset: 1

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Author

Amiram Eldar, Aug 31 2024

Keywords

Crossrefs

Programs

  • Mathematica
    evilQ[n_] := EvenQ[DigitCount[n, 2, 1]]; s[n_] := Module[{e = Max[FactorInteger[n][[;; , 2]]]}, If[evilQ[e], e, Nothing]]; s[1] = 0; Array[s, 1000]
  • PARI
    lista(kmax) = {my(e); print1(0, ", "); for(k = 2, kmax, e = vecmax(factor(k)[,2]); if(!(hammingweight(e) % 2), print1(e, ", ")));}

Formula

a(n) = A051903(A374590(n)).
Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k in A001969} (k * (1/zeta(k+1) - 1/zeta(k))) / d = 3.61461685523237846738..., where d = Sum_{k in A001969} (1/zeta(k+1) - 1/zeta(k)) = 0.12101890210392912747... is the asymptotic density of A374590.