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 A316323 #13 Jul 03 2018 20:51:03 %S A316323 0,1,3,4,2,8,9,7,6,15,16,14,5,13,24,25,23,12,11,22,35,36,34,21,10,20, %T A316323 33,48,49,47,32,19,18,31,46,63,64,62,45,30,17,29,44,61,80,81,79,60,43, %U A316323 28,27,42,59,78,99,100,98,77,58,41,26,40,57,76,97,120,121,119,96,75,56,39,38,55,74,95,118,143 %N A316323 The square array in A305615 read by antidiagonals. %F A316323 If 1 is added to every term we get the array in A269780, which has an explicit formula for the (i,j)-th term. %e A316323 The array in A305615 begins: %e A316323 ^ %e A316323 | %e A316323 4 |... ... ... ... ... %e A316323 +---------------+ %e A316323 3 | 9 14 12 10 |... %e A316323 +-----------+ | %e A316323 2 | 4 7 5 |11 |... %e A316323 +-------+ | | %e A316323 1 | 1 2 | 6 |13 |... %e A316323 +---+ | | | %e A316323 0 | 0 | 3 | 8 |15 |... %e A316323 +---+---+---+---+--- %e A316323 0 1 2 3 4 ... %e A316323 The first few antidiagonals are:L %e A316323 0, %e A316323 1, 3, %e A316323 4, 2, 8, %e A316323 9, 7, 6, 15, %e A316323 16, 14, 5, 13, 24, %e A316323 25, 23, 12, 11, 22, 35, %e A316323 36, 34, 21, 10, 20, 33, 48, %e A316323 ... %Y A316323 Cf. A305615, A269501, A269780. %K A316323 nonn,tabl %O A316323 0,3 %A A316323 _N. J. A. Sloane_, Jul 03 2018