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.

A370133 Numbers with no digit larger than 3 in primorial base, A049345.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99
Offset: 1

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Author

Antti Karttunen, Feb 11 2024

Keywords

Comments

Numbers k for which A328114(k) <= 3.
Numbers k such that A276086(k) is biquadratefree, A046100.

Crossrefs

Cf. A369639 (nonsquarefree numbers whose arithmetic derivative is in this sequence).
Cf. A370132, A276156 (subsequences).
Subsequence of A351576: a(n) differs from A351576(n-1) for the first time at n=97, where a(97) = 210, while A351576(96) = 120, a term not present here.

Programs

  • Mathematica
    q[n_] := Module[{k = n, p = 2, s = {}, r}, While[{k, r} = QuotientRemainder[k, p]; k != 0 || r != 0, AppendTo[s, r]; p = NextPrime[p]]; Count[s, ?(# > 3 &)] == 0]; Select[Range[0, 100], q] (* _Amiram Eldar, Mar 06 2024 *)
  • PARI
    ismaxprimobasedigit_at_most(n,k) = { my(s=0, p=2); while(n, if((n%p)>k, return(0)); n = n\p; p = nextprime(1+p)); (1); };
    isA370133(n) = ismaxprimobasedigit_at_most(n,3);