login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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
Sequence in context: A266017 A144469 A009101 * A303504 A135601 A296514
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
Edited by Robert Israel, Oct 29 2018
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 23 07:34 EDT 2024. Contains 371905 sequences. (Running on oeis4.)