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 A085005 #10 Oct 15 2013 04:06:02 %S A085005 1,3,4,4,3,3,4,4,3,1,0,0,1,1,0,0,1,3,4,4,5,7,10,12,13,13,14,16,17,17, %T A085005 16,16,17,19,20,20,21,23,26,28,29,31,34,38,41,43,44,46,49,51,52,52,53, %U A085005 55,56,56,55,55,56,58,59,59,60,62,65,67,68,68,69,71,72,72,71,71,72,72,71 %N A085005 A Von Koch curve related to the Golden ratio. %H A085005 Benoit Cloitre, <a href="/A085005/a085005.png">Plot of a(n) for n=1 up to 1362772</a> %F A085005 a(n)=(-1)*sum(i=1, n, sum(j=1, i, (-1)^floor(j*(1+sqrt(5))/2))) %F A085005 a(n) = 2*sum(k = 1, n, sum(i = 1, k, b(i)))-n*(n+1)/2, where b(k) = floor(phi*k)-2*floor(phi*k/2) %o A085005 (PARI) a(n)=(-1)*sum(i=1,n,sum(j=1,i,(-1)^floor(j*(1+sqrt(5))/2))) %Y A085005 Cf. A083035, A083036, A083037, A083038, A085002, A085003, A085004. %Y A085005 Cf. A094200, A094201. %K A085005 nonn %O A085005 1,2 %A A085005 _Benoit Cloitre_, Jun 17 2003