A199987 Numbers with digital product = 4.

4, 14, 22, 41, 114, 122, 141, 212, 221, 411, 1114, 1122, 1141, 1212, 1221, 1411, 2112, 2121, 2211, 4111, 11114, 11122, 11141, 11212, 11221, 11411, 12112, 12121, 12211, 14111, 21112, 21121, 21211, 22111, 41111, 111114, 111122, 111141, 111212, 111221, 111411

Offset: 1

Author

Jaroslav Krizek, Nov 13 2011

Keywords

• nonn
• base

Comments

Subsequence of A034051.

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Programs

Maple

f:= proc(d) local b,i,t;
   b:= (10^d-1)/9;
   op(sort([seq(b+3*10^i,i=0..d-1),
    seq(b+10^t[1]+10^t[2],t=combinat:-choose([$0..d-1],2))]))
end proc:
seq(f(d),d=1..6); # Robert Israel, Jan 13 2021

Mathematica

Select[Range[200000], Times @@ IntegerDigits[#] == 4 &] (* T. D. Noe, Nov 16 2011 *)