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A031962 Numbers for which the number of distinct base 10 digits is 3. 3
102, 103, 104, 105, 106, 107, 108, 109, 120, 123, 124, 125, 126, 127, 128, 129, 130, 132, 134, 135, 136, 137, 138, 139, 140, 142, 143, 145, 146, 147, 148, 149, 150, 152, 153, 154, 156, 157, 158, 159, 160, 162, 163, 164, 165, 167, 168, 169, 170, 172, 173, 174 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000 (first 648 terms from T. D. Noe)

MAPLE

f:= proc(d, b)  uses combinat; local S, Res, A1, A1p, A2, x1, x2;

     Res:= NULL:

     for S in choose({$0..b-1}, 3) do

       x1:= S[3]*(b^d-1)/(b-1);

       for A1 in powerset(d) minus {{}} do

         if S[1]=0 and member(d, A1) then next fi;

         x2:= x1 + (S[1]-S[3])*add(b^(j-1), j=A1);

         A1p:= {$1..d} minus A1;

         for A2 in powerset(A1p) minus {{}, A1p} do

           Res:= Res, x2 + (S[2]-S[3])*add(b^(j-1), j=A2);

         od

       od

     od;

     op(sort([Res]));

end proc:

f(3, 10), f(4, 10); # Robert Israel, Oct 29 2018

MATHEMATICA

Select[Range[100, 200], Length[Union[IntegerDigits[#]]] == 3 &] (* T. D. Noe, Dec 04 2012 *)

PROG

(PARI) isok(n) = #Set(digits(n)) == 3; \\ Michel Marcus, Oct 29 2018

CROSSREFS

Cf. A031956, A031957, A031958, A031959, A031960, A031961.

Sequence in context: A266017 A144469 A009101 * A303504 A135601 A296514

Adjacent sequences:  A031959 A031960 A031961 * A031963 A031964 A031965

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

EXTENSIONS

Edited by Robert Israel, Oct 29 2018

STATUS

approved

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Last modified April 6 10:28 EDT 2020. Contains 333273 sequences. (Running on oeis4.)