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.

A199989 Numbers with digital product = 8.

Original entry on oeis.org

8, 18, 24, 42, 81, 118, 124, 142, 181, 214, 222, 241, 412, 421, 811, 1118, 1124, 1142, 1181, 1214, 1222, 1241, 1412, 1421, 1811, 2114, 2122, 2141, 2212, 2221, 2411, 4112, 4121, 4211, 8111, 11118, 11124, 11142, 11181, 11214, 11222, 11241, 11412, 11421, 11811
Offset: 1

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Author

Jaroslav Krizek, Nov 13 2011

Keywords

Crossrefs

Subsequence of A034055.
Cf. A007954.

Programs

  • Maple
    f:= proc(d) local b,i,t;
       b:= (10^d-1)/9;
       op(sort([seq(b+7*10^i,i=0..d-1),seq(b+10^t[1]+3*10^t[2],t = combinat:-permute([$0..d-1],2)),seq(b+10^t[1]+10^t[2]+10^t[3],t=combinat:-choose([$0..d-1],3))]))
    end proc:
    seq(f(d),d=1..5); # Robert Israel, Jan 13 2021
  • Mathematica
    Select[Range[20000], Times @@ IntegerDigits[#] == 8 &] (* T. D. Noe, Nov 16 2011 *)