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.

A256875 Numbers divisible by prime(d) for each digit d in their base-5 representation, none of which may be zero.

Original entry on oeis.org

6, 12, 36, 156, 162, 186, 282, 306, 312, 546, 784, 786, 906, 912, 924, 936, 1246, 1536, 1806, 2674, 2814, 2856, 3906, 3912, 3936, 4032, 4056, 4062, 4074, 4284, 4536, 4656, 4662, 4686, 4746, 4914, 5796, 5922, 6174, 7032, 7056, 7062, 7182, 7434, 7656, 7662, 7686, 7782, 7806, 7812, 8064, 8106, 8946, 9072, 9114, 9282, 9324
Offset: 1

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Author

M. F. Hasler, Apr 11 2015

Keywords

Comments

Base-5 analog of A256786. See A256874 - A256879 for the base-3, ..., base-9 analogs.
See A256865 for a variant where divisibility by prime(d+1) is required instead.
From Robert Israel, Apr 04 2024: (Start)
Since digit 0 is not allowed, terms can't be divisible by 5, so digit 3 is also not allowed.
All terms are even. (End)

Crossrefs

Programs

  • Maple
    P:= [seq(ithprime(i),i=1..4)]:
    filter:= proc(n) local S,s;
      S:= convert(convert(n,base,5),set);
      if member(0,S) then return false fi;
      n mod mul(P[s],s=S) = 0
    end proc:
    select(filter, [$1..10^4]); # Robert Israel, Apr 04 2024
  • PARI
    is(n,b=5)=!for(i=1,#d=Set(digits(n,b)),(!d[i]||n%prime(d[i]))&&return)