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 A220516 #33 Jan 02 2021 04:52:32 %S A220516 0,1,3,8,2,4,9,7,5,15,24,10,6,14,16,25,23,11,13,17,35,48,26,22,12,18, %T A220516 34,36,49,47,27,21,19,33,37,63,80,50,46,28,20,32,38,62,64,81,79,51,45, %U A220516 29,31,39,61,65,99,120,82,78,52,44,30,40,60,66,98,100 %N A220516 Nonnegative integers in square maze arrangement T(n,k), read by antidiagonals, n>=0, k>=0. %C A220516 This sequence consists of 0 together with a permutation of the natural numbers. The structure is the same as A081344 but starting with 0, not 1. %C A220516 It appears that in the n-th layer there is at least a prime number <= g and also there is at least a prime number > g, where g is the number on the main diagonal, the n-th oblong number A002378(n), if n >= 1. %H A220516 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the nonnegative integers</a> %F A220516 a(n) = A081344(n+1) - 1. %F A220516 T(n,k) = n^2 + k , if n is odd and k<=n. %F A220516 T(n,k) = n(n + 2) - k, if n is even and k<=n. %F A220516 T(n,k) = k(k + 2) - n, if n is odd and n<k. %F A220516 T(n,k) = k^2 + n , if n is even and n<k. %e A220516 The first layer is [1, 2, 3] which looks like this: %e A220516 . 3, %e A220516 1, 2, %e A220516 The second layer is [4, 5, 6, 7, 8] which looks like this: %e A220516 . . 4 %e A220516 . . 5, %e A220516 8, 7, 6, %e A220516 Square array T(0,0)..T(10,10) begins: %e A220516 0, 3, 4, 15, 16, 35, 36, 63, 64, 99, 100,... %e A220516 1, 2, 5, 14, 17, 34, 37, 62, 65, 98, 101,... %e A220516 8, 7, 6, 13, 18, 33, 38, 61, 66, 97, 102,... %e A220516 9, 10, 11, 12, 19, 32, 39, 60, 67, 96, 103,... %e A220516 24, 23, 22, 21, 20, 31, 40, 59, 68, 95, 104,... %e A220516 25, 26, 27, 28, 29, 30, 41, 58, 69, 94, 105,... %e A220516 48, 47, 46, 45, 44, 43, 42, 57, 70, 93, 106,... %e A220516 49, 50, 51, 52, 53, 54, 55, 56, 71, 92, 107,... %e A220516 80, 79, 78, 77, 76, 75, 74, 73, 72, 91, 108,... %e A220516 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 109,... %e A220516 120, 119, 118, 117, 116, 115, 114, 113, 112, 111, 110,... %e A220516 ... %Y A220516 Main diagonal is A002378. %Y A220516 Cf. A000040, A000290, A002620, A081344, A220508. %K A220516 nonn,tabl %O A220516 0,3 %A A220516 _Omar E. Pol_, Feb 09 2013