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 A154806 #12 Apr 13 2018 09:35:46
%S A154806 15,240,3855,61680,986895,15790320,252645135,4042322160,64677154575,
%T A154806 1034834473200,16557351571215,264917625139440,4238682002231055,
%U A154806 67818912035696880,1085102592571150095,17361641481138401520
%N A154806 Numbers such that every run length in base 2 is 4.
%C A154806 a(n) is the number whose binary representation is A154805(n).
%H A154806 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (16,1,-16).
%F A154806 Conjecture: a(n) = 1/17*2^(4*n+4) + 15/34*(-1)^(n+1) - 1/2. - _Vaclav Kotesovec_, Nov 30 2012
%F A154806 Empirical g.f.: 15*x / ((x-1)*(x+1)*(16*x-1)). - _Colin Barker_, Sep 16 2013
%t A154806 LinearRecurrence[{16,1,-16},{15,240,3855},20] (* _Harvey P. Dale_, Apr 13 2018 *)
%Y A154806 Cf. A043291, A097262, A152776, A154805, A154808.
%K A154806 easy,nonn
%O A154806 1,1
%A A154806 _Omar E. Pol_, Jan 25 2009
%E A154806 More terms from _Sean A. Irvine_, Feb 21 2010