A043675 - OEIS

%I #16 Apr 25 2021 12:18:12

%S 16,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,35,36,37,38,39,40,

%T 41,42,43,44,45,46,47,48,49,50,52,53,54,55,56,57,58,59,60,61,62,63,64,

%U 65,66,67,69,70,71,72,73,74,75,76,77,78,79

%N Numbers whose base-16 representation has exactly 2 runs.

%H Robert Israel, <a href="/A043675/b043675.txt">Table of n, a(n) for n = 1..10000</a>

%p N:= 3; # get all results <= 16^N

%p sort([seq(seq(seq(seq((a*(16^n-16^k)+b*(16^k-1))/15, k=1..n-1),n=2..N),

%p b={$0..15} minus {a}),a=1..15)]); # _Robert Israel_, Dec 11 2015

%K nonn,base

%O 1,1

%A _Clark Kimberling_