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 A277572 #6 Nov 07 2016 09:13:19
%S A277572 1,4,6,7,10,13,16,19,22,24,25,28,31,34,36,37,40,42,43,46,49,52,55,58,
%T A277572 60,61,64,67,70,73,76,78,79,82,85,88,91,94,96,97,100,103,106,109,112,
%U A277572 114,115,118,121,124,127,130,132,133,136,139,142,144,145,148
%N A277572 (1/2)*A277568.
%H A277572 Clark Kimberling, <a href="/A277572/b277572.txt">Table of n, a(n) for n = 1..10000</a>
%t A277572 z = 260; a[b_] := Table[Mod[n/b^IntegerExponent[n, b], b], {n, 1, z}]
%t A277572 p[b_, d_] := Flatten[Position[a[b], d]]
%t A277572 p[6, 2]/2 (* A277572 *)
%t A277572 p[6, 3]/3 (* A277573 *)
%t A277572 p[6, 4]/2 (* A277574 *)
%Y A277572 Cf. A277568, A277573, A277574.
%K A277572 nonn,easy
%O A277572 1,2
%A A277572 _Clark Kimberling_, Nov 01 2016