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 A178400 #13 Mar 30 2012 18:57:11 %S A178400 4,5,5,6,7,7,8,8,9,9,10,10,10,12,12,13,13,14,14,14,15,15,16,16,16,16, %T A178400 18,18,18,18,19,19,20,20,20,20,21,21,22,22,22,22,22,24,24,24,24,24,24, %U A178400 25,25,26,26,26,26,26,28,28,28,28,30,30,30,30,30,30,31 %N A178400 Sums of two primes, an array by antidiagonals. %C A178400 The joint-rank array of this array is A178431. %F A178400 T(i,j)=p(i)+p(j), where p=(2,3,5,7,...)=A000040. %e A178400 Northwest corner: %e A178400 4....5....7....9...13... %e A178400 5....6....8...10...12... %e A178400 7....8...10...12...16... %e A178400 9...10...12...14...14... %e A178400 T(1,1)=2+2=4. %Y A178400 Cf. A000040, A014092. %K A178400 nonn,tabl %O A178400 1,1 %A A178400 _Clark Kimberling_, Dec 21 2010