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 A129392 #9 May 20 2014 14:52:32 %S A129392 1,1,3,1,1,-5,-7,-5,1,1,7,5,3,5,7,1,1,3,1,-9,-15,-9,1,3,1,1,-33,-35, %T A129392 -5,29,43,29,-5,-35,-33,1,1,91,89,31,-23,-49,-55,-49,-23,31,89,91,1,1, %U A129392 -137,-139,-93,-43,19,85,115,85,19,-43,-93,-139,-137,1,1,51,49,135,225,183,1,-201,-287,-201,1,183,225,135,49,51,1,1,399 %N A129392 Triangle read by rows: T(r,c)=T(r,c-1)+T(r,c+1)+T(r-1,c-1). %C A129392 All edge elements are 1 and the triangle is symmetric about the central line. For all elements x inside the triangle %C A129392 ..a.. %C A129392 .bxc. %C A129392 we have x=a+b+c. The triangle is symmetric. The top of the triangle thus is %C A129392 ........1 %C A129392 .....1..3..1 %C A129392 ..1.-5.-7.-5..1 %C A129392 1..7..5..3..5..7..1 %H A129392 R. J. Mathar, <a href="/A129392/a129392.pdf">Comments on A129392, A129394 and A129396</a> %Y A129392 Cf. A129393, A129394, A129396, A129398. %K A129392 sign,tabf %O A129392 0,3 %A A129392 _Jonas Wallgren_, Apr 13 2007 %E A129392 More terms from _R. J. Mathar_, Jan 17 2008