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A039402
Numbers whose base-10 representation has the same nonzero number of 1's and 2's.
1
12, 21, 102, 120, 123, 124, 125, 126, 127, 128, 129, 132, 142, 152, 162, 172, 182, 192, 201, 210, 213, 214, 215, 216, 217, 218, 219, 231, 241, 251, 261, 271, 281, 291, 312, 321, 412, 421, 512, 521, 612, 621, 712, 721, 812, 821, 912, 921, 1002, 1020
OFFSET
1,1
LINKS
MAPLE
filter:= proc(n) local L, t;
L:= convert(n, base, 10);
t:= numboccur(1, L);
t > 0 and t = numboccur(2, L)
end proc:
select(filter, [$1..1000]); # Robert Israel, Oct 29 2024
CROSSREFS
Sequence in context: A157157 A218043 A048344 * A043225 A111066 A201015
KEYWORD
nonn,base,easy,changed
STATUS
approved