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A199986 Numbers with digital product = 2.

%I A199986 #27 Feb 12 2021 14:52:16
%S A199986 2,12,21,112,121,211,1112,1121,1211,2111,11112,11121,11211,12111,
%T A199986 21111,111112,111121,111211,112111,121111,211111,1111112,1111121,
%U A199986 1111211,1112111,1121111,1211111,2111111,11111112,11111121,11111211,11112111,11121111,11211111
%N A199986 Numbers with digital product = 2.
%C A199986 Subsequence of A034049.
%H A199986 Robert Israel, <a href="/A199986/b199986.txt">Table of n, a(n) for n = 1..10000</a>
%H A199986 S. Giraudo, <a href="http://arxiv.org/abs/1306.6938">Combinatorial operads from monoids</a>, arXiv preprint arXiv:1306.6938 [math.CO], 2013-2015. See Sect. 3.2.1.
%p A199986 f:= proc(d) local b,i;
%p A199986   b:= (10^d-1)/9;
%p A199986   seq(b+10^i,i=0..d-1);
%p A199986 end proc:
%p A199986 seq(f(d),d=1..9); # _Robert Israel_, Jan 13 2021
%o A199986 (PARI) one(n)=if(n,10^n\9,"")
%o A199986 for(n=0,9,for(m=0,n,print1(one(n-m)2one(m)", "))) \\ _Charles R Greathouse IV_, Nov 13 2011
%o A199986 (Python)
%o A199986 def athrough(k1s):
%o A199986   return [int("1"*(i-j)+"2"+"1"*j) for i in range(k1s+1) for j in range(i+1)]
%o A199986 print(athrough(8)) # _Michael S. Branicky_, Feb 12 2021
%K A199986 nonn,easy,base
%O A199986 1,1
%A A199986 _Jaroslav Krizek_, Nov 13 2011