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 A341458 #11 Feb 14 2021 13:04:31 %S A341458 1,2,2,3,1,3,4,5,5,4,5,6,1,6,5,6,3,7,7,3,6,7,4,2,1,2,4,7,8,8,8,8,8,8, %T A341458 8,8,9,7,4,2,1,2,4,7,9,10,17,6,3,7,7,3,6,17,10,11,18,33,5,6,1,6,5,33, %U A341458 18,11,12,22,39,57,4,5,5,4,57,39,22,12 %N A341458 Unique square array T(n, k) read by antidiagonals, n, k > 0, such that A000069(T(n, k)) = A341288(A000069(n), A000069(k)). %C A341458 The positive integers equipped with T form a group. %C A341458 Every row (and column) is a self-inverse permutation of the positive integers. %H A341458 Rémy Sigrist, <a href="/A341458/b341458.txt">Table of n, a(n) for n = 1..8385</a> %H A341458 Rémy Sigrist, <a href="/A341288/a341288_1.png">Colored representation of the table for 1 <= n, k <= 128</a> %H A341458 Rémy Sigrist, <a href="/A341458/a341458.gp.txt">PARI program for A341458</a> %F A341458 T(n, k) = T(k, n). %F A341458 T(n, 1) = n. %F A341458 T(n, n) = 1. %e A341458 Array T(n, k) begins: %e A341458 n\k| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 %e A341458 ---+-------------------------------------------------------------------------- %e A341458 1| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 %e A341458 2| 2 1 5 6 3 4 8 7 17 18 22 21 20 19 23 24 %e A341458 3| 3 5 1 7 2 8 4 6 33 39 35 37 36 38 34 40 %e A341458 4| 4 6 7 1 8 2 3 5 57 63 62 60 61 59 58 64 %e A341458 5| 5 3 2 8 1 7 6 4 65 71 70 68 69 67 66 72 %e A341458 6| 6 4 8 2 7 1 5 3 89 95 91 93 92 94 90 96 %e A341458 7| 7 8 4 3 6 5 1 2 105 106 110 109 108 107 111 112 %e A341458 8| 8 7 6 5 4 3 2 1 113 114 115 116 117 118 119 120 %e A341458 9| 9 17 33 57 65 89 105 113 1 25 41 49 73 81 97 121 %e A341458 10| 10 18 39 63 71 95 106 114 25 1 56 48 88 80 121 97 %e A341458 11| 11 22 35 62 70 91 110 115 41 56 1 32 104 121 80 81 %e A341458 12| 12 21 37 60 68 93 109 116 49 48 32 1 121 104 88 73 %e A341458 13| 13 20 36 61 69 92 108 117 73 88 104 121 1 32 48 49 %e A341458 14| 14 19 38 59 67 94 107 118 81 80 121 104 32 1 56 41 %e A341458 15| 15 23 34 58 66 90 111 119 97 121 80 88 48 56 1 25 %e A341458 16| 16 24 40 64 72 96 112 120 121 97 81 73 49 41 25 1 %o A341458 (PARI) See Links section. %Y A341458 Cf. A000069, A341288. %Y A341458 See A341487 and A341489 for the second and third rows, respectively. %K A341458 nonn,tabl,base %O A341458 1,2 %A A341458 _Rémy Sigrist_, Feb 12 2021