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A031962 Numbers with exactly three distinct base-10 digits. 6
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 *)

Select[Range[100, 200], Count[DigitCount[#], 0]==7&] (* Harvey P. Dale, May 22 2020 *)

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 December 3 20:52 EST 2022. Contains 358543 sequences. (Running on oeis4.)