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 A092899 #12 Jun 13 2015 00:51:19
%S A092899 1,3,7,15,19,27,31,39,43,51,55,63,67,75,79,87,91,99,103,111,115,123,
%T A092899 127,135,139,147,151,159,163,171,175,183,187,195,199,207,211,219,223,
%U A092899 231,235,243,247,255,259,267,271,279,283,291,295,303,307,315,319,327,331
%N A092899 Expansion of (1+2x+3x^2+6x^3)/((1+x)(1-x)^2).
%C A092899 mod(A092899(n),4)=1,3,3,3,... = sum{k=0..n, mod(2^k,4)} Partial sums of 1,2,4,8,4,8,4,8....
%H A092899 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1).
%F A092899 a(n)=4floor((n+1)/2)+4n-5+6*0^n; a(n)=sum{k=0...n, mod(A078008(k), 4)}+sum{k=0..n, 2*mod(A001045(k), 4)}.
%F A092899 For n > 0, a(n) = 6*n - 4 - (-1)^n; a(n+3) = a(n+2) + a(n+1) - a(n) - _Warut Roonguthai_, Oct 19 2005
%K A092899 easy,nonn
%O A092899 0,2
%A A092899 _Paul Barry_, Mar 12 2004