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.

A241142 Numbers n such that n and 6n share at least one digit.

Original entry on oeis.org

2, 4, 6, 8, 10, 12, 14, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 34, 36, 38, 39, 40, 41, 42, 44, 46, 48, 49, 50, 52, 53, 54, 56, 58, 59, 60, 61, 62, 63, 64, 66, 68, 70, 72, 73, 74, 75, 76, 78, 79, 80, 81, 82, 83, 84, 85, 86, 88, 90, 92, 94, 95, 96, 98, 99, 100
Offset: 1

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Author

Robert G. Wilson v, Apr 16 2014

Keywords

Comments

All numbers n which are congruent to 0 (mod 6) have this characteristic.
All even n have this characteristic, because n == 6n mod 10. Robert Israel, Apr 17 2014

Examples

			12 is in the sequence since 12 and 6*12 = 72 and together they share the digit 2.
		

Crossrefs

Programs

  • Maple
      N:= 10000;  # to get all entries up to N
    filter:= proc(n) local L, L6;
       L:= convert(convert(n,base,10),set);
       L6:= convert(convert(6*n,base,10),set);
       L intersect L6 <> {};
    end;
    select(filter, [$1..N]); # Robert Israel, Apr 17 2014
  • Mathematica
    fQ[n_] := Intersection[ IntegerDigits[ n], IntegerDigits[6 n]] != {}; Select[ Range[ 100], fQ]
  • PARI
    isok(n) = #setintersect(Set(digits(n)), Set(digits(6*n))); \\ Michel Marcus, Apr 17 2014