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 A171698 #7 Jul 22 2025 07:32:01 %S A171698 1,1,1,2,2,2,6,6,4,4,20,20,14,8,8,70,70,50,30,16,16,252,252,182,112, %T A171698 62,32,32,924,924,672,420,238,126,64,64 %N A171698 Square 'central binomial coefficients'-array read by antidiagonals. %C A171698 Antidiagonals sum up to A000984. %e A171698 Example with 0's added: %e A171698 0,1,1,2,4,8,.. %e A171698 0,1,2,4,8,16,.. %e A171698 0,2,6,14,30,.. %e A171698 Row 2 (binomial): 0+1=1,1+1=2,... %e A171698 Row 3 (trinomial): 0+1+1=2,2+2+2=6,6+4+4=14... %Y A171698 Cf. A000984, A011782, A009766, A007318. %K A171698 nonn,tabl %O A171698 1,4 %A A171698 _Mark Dols_, Dec 15 2009