A039170 - OEIS

%I #15 Jun 26 2021 05:48:55

%S 0,2,3,4,5,6,8,9,10,18,22,24,25,26,27,28,30,31,32,33,35,36,37,38,39,

%T 41,42,43,44,46,47,48,49,50,52,53,54,55,57,58,59,60,61,63,64,65,66,68,

%U 69,70,71,72,74,75,76,78,88,90,91,92,93,94,96,97,98,99,101,102,103

%N Numbers whose base-11 representation has the same number of 1's and 7's.

%H G. C. Greubel, <a href="/A039170/b039170.txt">Table of n, a(n) for n = 1..5000</a>

%t Select[Range[0, 500], DigitCount[#, 11, 1] == DigitCount[#, 11, 7] &] (* _G. C. Greubel_, Nov 01 2017 *)

%o (PARI) isok(n) = my(d=digits(n, 11)); #select(x->(x==1), d) == #select(x->(x==7), d); \\ _Michel Marcus_, Nov 01 2017

%K nonn,base,easy

%O 1,2

%A _Olivier Gérard_