[go: up one dir, main page]

login
A292125
Positive numbers n such that the set of base-7 digits of n equals both the set of base-8 digits of n and the set of base-9 digits of n.
1
1, 2, 3, 4, 5, 6, 32942, 103302, 142489, 178248, 263180, 361369, 362370, 378454, 540929, 540940, 567333, 567337, 590697, 693302, 723659, 726195, 743217, 829792, 888934, 1070221, 1073830, 1074177, 1083411, 1083738, 1090352, 1106956, 1129738, 1139557, 1139881, 1201762, 1249562
OFFSET
1,2
LINKS
EXAMPLE
32942 in base 7 is 165020; in base 8 is 100256; and in base 9 is 50162. The set of digits for all three is {0, 1, 2, 5, 6}.
MAPLE
filter:= proc(n) local S;
S:= convert(convert(n, base, 9), set);
nops(S intersect {7, 8})=0 and evalb(convert(convert(n, base, 8), set)=S) and evalb(convert(convert(n, base, 7), set)=S)
end proc:
select(filter, [$1..6, seq(seq(9*a+b, b=0..6), a=1..7*9^5-1)]); # Robert Israel, Sep 11 2017
MATHEMATICA
Select[Range[5/4*10^6], Function[k, SameQ @@ Map[Union@ IntegerDigits[k, #] &, {7, 8, 9}]]] (* Michael De Vlieger, Sep 10 2017 *)
PROG
(PARI) isok(n) = my(s7 = Set(digits(n, 7)), s8 = Set(digits(n, 8)), s9 = Set(digits(n, 9))); (s7 == s8) && (s8 == s9); \\ Michel Marcus, Sep 09 2017
CROSSREFS
Subsequence of A037438.
Sequence in context: A153678 A004901 A004912 * A330928 A164699 A228050
KEYWORD
nonn,base
AUTHOR
Paul Lusch, Sep 08 2017
EXTENSIONS
More terms from Michel Marcus, Sep 09 2017
STATUS
approved