A039605 Numbers whose base-12 representation has the same nonzero number of 1's and 3's.

15, 37, 147, 171, 180, 182, 184, 185, 186, 187, 188, 189, 190, 191, 195, 207, 219, 231, 243, 255, 267, 279, 303, 325, 433, 444, 446, 448, 449, 450, 451, 452, 453, 454, 455, 457, 481, 493, 505, 517, 529, 541, 553, 565, 591, 613, 735, 757, 879, 901, 1023

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

filter:= proc(n) local L, v;
   L:= convert(n, base, 12);
   v:= numboccur(1, L);
   v > 0 and v = numboccur(3, L)
end proc:
select(filter, [$1..2000]); # Robert Israel, Dec 31 2019

Mathematica

Select[Range[1100], DigitCount[#, 12, 1]==DigitCount[#, 12, 3]>0&]  (* Harvey P. Dale, Apr 21 2011 *)

Crossrefs

Sequence in context: A147221 A051461 A321383 * A032654 A320721 A086096

Adjacent sequences: A039602 A039603 A039604 * A039606 A039607 A039608

Keyword

nonn,base,easy

Author

Olivier Gérard

Status

approved