This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A277569 #15 Oct 03 2023 22:22:37
%S A277569 3,9,15,18,21,27,33,39,45,51,54,57,63,69,75,81,87,90,93,99,105,108,
%T A277569 111,117,123,126,129,135,141,147,153,159,162,165,171,177,183,189,195,
%U A277569 198,201,207,213,219,225,231,234,237,243,249,255,261,267,270,273,279
%N A277569 Numbers k such that k/6^m == 3 (mod 6), where 6^m is the greatest power of 6 that divides k.
%C A277569 Positions of 3 in A277544.
%C A277569 Numbers having 3 as rightmost nonzero digit in base 6. This is one sequence in a 5-way splitting of the positive integers; the other four are indicated in the Mathematica program. Every term is a multiple of 3; see A277573.
%C A277569 Numbers m having the property that tau(3m) < tau(2m) where tau(m) = A000005(m) (i.e., the number of divisors of m). - _Gary Detlefs_, Jan 28 2019
%H A277569 Clark Kimberling, <a href="/A277569/b277569.txt">Table of n, a(n) for n = 1..10000</a>
%F A277569 a(n) = 5n + O(log n). - _Charles R Greathouse IV_, Nov 03 2016
%p A277569 with(numtheory): for n from 1 to 279 do if tau(3*n)<tau(2*n) then print(n) fi od # _Gary Detlefs_, Jan 28 2019
%t A277569 z = 260; a[b_] := Table[Mod[n/b^IntegerExponent[n, b], b], {n, 1, z}]
%t A277569 p[b_, d_] := Flatten[Position[a[b], d]]
%t A277569 p[6, 1] (* A277567 *)
%t A277569 p[6, 2] (* A277568 *)
%t A277569 p[6, 3] (* this sequence *)
%t A277569 p[6, 4] (* A277570 *)
%t A277569 p[6, 5] (* A277571 *)
%o A277569 (PARI) is(n)=(n/6^valuation(n,6))%6==3 \\ _Charles R Greathouse IV_, Nov 03 2016
%Y A277569 Cf. A277544, A277567, A277568, A277573.
%K A277569 nonn,easy
%O A277569 1,1
%A A277569 _Clark Kimberling_, Nov 01 2016