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.

Showing 1-2 of 2 results.

A256876 Numbers divisible by prime(d) for each digit d in their base-6 representation, none of which may be zero.

Original entry on oeis.org

15, 28, 154, 280, 525, 555, 735, 910, 1036, 1078, 1666, 3795, 4270, 4665, 4690, 5446, 5530, 5572, 5775, 5950, 6202, 7755, 9352, 9982, 10108, 13888, 14014, 15400, 18705, 18885, 18915, 19965, 19995, 20175, 20475, 20625, 21735, 21945, 22605, 26445, 26475, 26565, 26655, 27735, 27995, 28000, 28035
Offset: 1

Views

Author

M. F. Hasler, Apr 11 2015

Keywords

Comments

Base-6 analog of A256786. See A256874 - A256879 for the base-4, ..., base-9 analogs.
See A256866 for a variant where divisibility by prime(d+1) is required instead.
Since digit 0 is not allowed, no terms are divisible by 6, so digits 1 and 2 can't both be present. - Robert Israel, Apr 04 2024

Crossrefs

Programs

  • Maple
    P:= [2,3,5,7,11]:
    filter6:= proc(n) local S,s;
      S:= convert(convert(n,base,6),set);
      if member(0,S) then return false fi;
      n mod mul(P[s],s=S) = 0
    end proc:
    S1:= {1}; S2:= {2}; S0:= {3,4,5}: R:= select(filter6, S0 union S1 union S2):
    for i from 2 to 10 do
      S1:= map(t -> (6*t+1, 6*t+3,6*t+4, 6*t+5), S1) union map(t -> 6*t+1, S0);
      S2:= map(t -> (6*t+2, 6*t+3, 6*t+4, 6*t+5), S2) union map(t -> 6*t+2, S0);
      S0:= map(t -> (6*t+3,6*t+4,6*t+5), S0);
      R:= R union select(filter6, S0) union select(filter6, S1) union select(filter6, S2);
    od:
    sort(convert(R,list)); # Robert Israel, Apr 04 2024
  • Mathematica
    ndpQ[n_]:=Module[{ds=Union[IntegerDigits[n,6]]},FreeQ[ds,0]&&And@@ Table[ Divisible[n,Prime[i]],{i,ds}]]; Select[Range[20000],ndpQ] (* Harvey P. Dale, May 29 2015 *)
  • PARI
    is(n,b=6)=!for(i=1,#d=Set(digits(n,b)),(!d[i]||n%prime(d[i]))&&return)

Extensions

More terms from Robert Israel, Apr 04 2024

A256878 Numbers divisible by prime(d) for each digit d in their base-8 representation, none of which may be zero.

Original entry on oeis.org

18, 35, 78, 84, 90, 138, 210, 255, 330, 429, 588, 594, 910, 1098, 1170, 1275, 1386, 1530, 1755, 1820, 1950, 2156, 2275, 2706, 3315, 3510, 3927, 3978, 4746, 4758, 4794, 4900, 4914, 5202, 5610, 5850, 6244, 6300, 6412, 6930, 7254, 7410, 7462, 7566, 8778, 8850, 9042, 9354, 9435, 9492
Offset: 1

Views

Author

M. F. Hasler, Apr 11 2015

Keywords

Comments

Base-8 analog of A256786. See A256874 - A256879 for the base-4, ..., base-9 analogs.
See A256868 for a variant where divisibility by prime(d+1) is required instead.

Crossrefs

Programs

  • PARI
    is(n,b=8)=!for(i=1,#d=Set(digits(n,b)),(!d[i]||n%prime(d[i]))&&return)
Showing 1-2 of 2 results.