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Numbers whose base-4 representation contains exactly two 1's and two 3's.
0

%I #12 May 21 2023 12:23:09

%S 95,119,125,215,221,245,287,311,317,335,367,371,379,380,382,415,439,

%T 445,455,461,467,475,476,478,487,493,497,500,502,505,607,631,637,727,

%U 733,757,791,797,821,839,845,851,859,860,862,871

%N Numbers whose base-4 representation contains exactly two 1's and two 3's.

%Y Cf. A007090.

%K nonn,base

%O 1,1

%A _Clark Kimberling_