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A199986 Numbers with digital product = 2. 3
2, 12, 21, 112, 121, 211, 1112, 1121, 1211, 2111, 11112, 11121, 11211, 12111, 21111, 111112, 111121, 111211, 112111, 121111, 211111, 1111112, 1111121, 1111211, 1112111, 1121111, 1211111, 2111111, 11111112, 11111121, 11111211, 11112111, 11121111, 11211111 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Subsequence of A034049.
LINKS
S. Giraudo, Combinatorial operads from monoids, arXiv preprint arXiv:1306.6938 [math.CO], 2013-2015. See Sect. 3.2.1.
MAPLE
f:= proc(d) local b, i;
b:= (10^d-1)/9;
seq(b+10^i, i=0..d-1);
end proc:
seq(f(d), d=1..9); # Robert Israel, Jan 13 2021
PROG
(PARI) one(n)=if(n, 10^n\9, "")
for(n=0, 9, for(m=0, n, print1(one(n-m)2one(m)", "))) \\ Charles R Greathouse IV, Nov 13 2011
(Python)
def athrough(k1s):
return [int("1"*(i-j)+"2"+"1"*j) for i in range(k1s+1) for j in range(i+1)]
print(athrough(8)) # Michael S. Branicky, Feb 12 2021
CROSSREFS
Sequence in context: A053896 A155890 A213969 * A336528 A077410 A211029
KEYWORD
nonn,easy,base
AUTHOR
Jaroslav Krizek, Nov 13 2011
STATUS
approved

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Last modified March 19 09:40 EDT 2024. Contains 370981 sequences. (Running on oeis4.)