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Numbers whose largest decimal digit is 2.
9

%I #29 Mar 03 2019 03:01:57

%S 2,12,20,21,22,102,112,120,121,122,200,201,202,210,211,212,220,221,

%T 222,1002,1012,1020,1021,1022,1102,1112,1120,1121,1122,1200,1201,1202,

%U 1210,1211,1212,1220,1221,1222,2000,2001,2002,2010,2011,2012,2020,2021,2022

%N Numbers whose largest decimal digit is 2.

%C Number of terms less than 10^n is 3^n-2^n, i.e., A001047(n). - _Chai Wah Wu_, Nov 06 2016 [extended by _Felix Fröhlich_, Nov 07 2016]

%C Numbers n such that A054055(n) = 2. - _Felix Fröhlich_, Nov 07 2016

%H Alois P. Heinz, <a href="/A277964/b277964.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 terms from Colin Barker)

%p N:= 6: # to get all terms of at most N digits

%p R:= 2: B:= {1}: C:= {1,2}:

%p for d from 2 to N do B:= map(t -> (10*t,10*t+1),B);

%p C:= map(t -> (10*t,10*t+1,10*t+2),C);

%p R:= R, op(sort(convert(C minus B,list)))

%p od:

%p R; # _Robert Israel_, Nov 07 2016

%t A277964Q = Max[IntegerDigits[#]] == 2 &; Select[Range[2000], A277964Q] (* _JungHwan Min_, Nov 06 2016 *)

%o (PARI) L=List(); for(n=1, 10000, if(vecmax(digits(n))==2, listput(L, n))); Vec(L)

%o (GAP) Filtered([1..2100],n->Maximum(ListOfDigits(n))=2); # _Muniru A Asiru_, Mar 01 2019

%Y Cf. A007088, A277965, A277966.

%K nonn,base

%O 1,1

%A _Colin Barker_, Nov 06 2016