OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
31 = 1011_3; 37 = 1101_3; 39 = 1110_3; 95 = 10112_3.
MAPLE
f:= proc(d) local x, R, i, j, j3;
x:= 3^d-1;
op(sort([seq(seq(x - add(3^j, j = j3) - 2*3^i, i= {$0..d-2} minus j3) , j3 =combinat:-choose({$0..d-1}, 3))]))
end proc:
map(f, [$4..6]); # Robert Israel, Apr 20 2021
MATHEMATICA
Select[Range[500], DigitCount[#, 3, 0]==1&&DigitCount[#, 3, 1]==3&] (* Harvey P. Dale, Jul 12 2019 *)
PROG
(PARI) isok(k) = my(d=digits(k, 3)); (#select(x->(x==0), d) == 1) && (#select(x->(x==1), d) == 3); \\ Michel Marcus, Apr 21 2021
CROSSREFS
KEYWORD
AUTHOR
STATUS
approved