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 A206716 #6 Mar 30 2012 18:58:12
%S A206716 1,2,3,4,6,8,9,12,13,15,16,17,18,19,21,24,25,26,27,30,32,33,34,35,36,
%T A206716 38,39,42,43,45,47,48,49,50,51,52,54,60,64,65,66,67,68,70,72,73,76,78,
%U A206716 84,86,90,91,94,96,97,98,99,100,102,104,105,108,117,120,121,128
%N A206716 (1/5)A206715.
%C A206716 It is conjectured that all the terms of this sequence are integers; this may be equivalent to the conjecture at A131853.
%t A206716 t = Table[IntegerDigits[n, 2], {n, 1, 3000}];
%t A206716 b[n_] := Reverse[Table[x^k, {k, 0, n}]]
%t A206716 p[n_, x_] := p[n, x] = t[[n]].b[-1 + Length[t[[n]]]]
%t A206716 TableForm[Table[{n, p[n, x], Factor[p[n, x]]},
%t A206716 {n, 1, 16}]]
%t A206716 u = {}; Do[n++; If[(p[n, x] /. x -> I) == 0,
%t A206716 AppendTo[u, n]], {n, 800}]
%t A206716 u (* A206715 *)
%t A206716 u/5 (* A206716 *)
%Y A206716 Cf. A131853, A206074, A206715.
%K A206716 nonn
%O A206716 1,2
%A A206716 _Clark Kimberling_, Feb 11 2012