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A039088
Numbers whose base-9 representation has the same number of 1's and 6's.
1
0, 2, 3, 4, 5, 7, 8, 15, 18, 20, 21, 22, 23, 25, 26, 27, 29, 30, 31, 32, 34, 35, 36, 38, 39, 40, 41, 43, 44, 45, 47, 48, 49, 50, 52, 53, 55, 63, 65, 66, 67, 68, 70, 71, 72, 74, 75, 76, 77, 79, 80, 87, 105, 114, 123, 132, 135, 137, 138, 139, 140, 142, 143, 150, 159, 162
OFFSET
1,2
LINKS
MAPLE
filter:= proc(n) local L;
L:= convert(n, base, 9);
numboccur(1, L) = numboccur(6, L)
end proc:
select(filter, [$0..1000]); # Robert Israel, Mar 13 2018
PROG
(PARI) isok(n) = {my(d = digits(n, 9)); #select(x->(x==1), d) == #select(x->(x==6), d); } \\ Michel Marcus, Mar 13 2018
CROSSREFS
Cf. A007095.
Sequence in context: A285929 A309880 A054762 * A111794 A030290 A099088
KEYWORD
nonn,base,easy
STATUS
approved