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 A109225 #6 Mar 30 2012 18:50:50 %S A109225 1,1,1,1,2,1,1,3,4,1,1,4,7,6,1,1,5,12,13,8,1,1,6,17,26,21,10,1,1,7,24, %T A109225 43,48,31,12,1,1,8,31,68,91,80,43,14,1,1,9,40,99,160,171,124,57,16,1, %U A109225 1,10,49,140,259,332,295,182,73,18,1,1,11,60,189,400,591,628,477 %N A109225 Triangle read by rows: T(n,0) = T(n,n) = 1 and for 0 < k < n: T(n,k) = T(n-1,k-1) + 1 - T(n-1,k-1) mod 2 + T(n-1,k). %C A109225 Row sums give A084172, the generalized Jacobsthal numbers; %C A109225 T(n,1) = n for n>0; %C A109225 T(n,2) = A074148(n) for n>1. %H A109225 <a href="/index/Pas#Pascal">Index entries for triangles and arrays related to Pascal's triangle</a> %Y A109225 Cf. A007318. %K A109225 nonn,tabl %O A109225 1,5 %A A109225 _Reinhard Zumkeller_, Jun 23 2005