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 A316586 #7 Jul 10 2018 21:17:33
%S A316586 1,1,1,1,4,1,1,3,2,1,1,4,9,8,1,1,1,8,9,2,1,1,6,1,32,21,8,1,1,1,18,1,
%T A316586 32,27,2,1,1,4,1,24,25,32,57,16,1,1,3,8,1,42,1,44,33,2,1,1,4,9,32,1,
%U A316586 108,1,160,99,8,1,1,1,2,9,32,1,114,1,56,63,2,1
%N A316586 Array read by antidiagonals: T(n,k) is the number of elements x in SL(2,Z_n) with x^k == I mod n where I is the identity matrix.
%C A316586 All columns are multiplicative.
%F A316586 T(n,k) = Sum_{d|k} A316564(n, d).
%F A316586 Conjecture: T(p,p) = p^2 for p prime.
%e A316586 Array begins:
%e A316586 ================================================
%e A316586 n\k | 1 2 3 4 5 6 7 8 9 10
%e A316586 ------+-----------------------------------------
%e A316586 1 | 1 1 1 1 1 1 1 1 1 1 ...
%e A316586 2 | 1 4 3 4 1 6 1 4 3 4 ...
%e A316586 3 | 1 2 9 8 1 18 1 8 9 2 ...
%e A316586 4 | 1 8 9 32 1 24 1 32 9 8 ...
%e A316586 5 | 1 2 21 32 25 42 1 32 21 50 ...
%e A316586 6 | 1 8 27 32 1 108 1 32 27 8 ...
%e A316586 7 | 1 2 57 44 1 114 49 128 57 2 ...
%e A316586 8 | 1 16 33 160 1 144 1 256 33 16 ...
%e A316586 9 | 1 2 99 56 1 198 1 56 243 2 ...
%e A316586 10 | 1 8 63 128 25 252 1 128 63 200 ...
%e A316586 11 | 1 2 111 112 265 222 1 112 111 530 ...
%e A316586 12 | 1 16 81 256 1 432 1 256 81 16 ...
%e A316586 13 | 1 2 183 184 1 366 469 184 183 2 ...
%e A316586 14 | 1 8 171 176 1 684 49 512 171 8 ...
%e A316586 15 | 1 4 189 256 25 756 1 256 189 100 ...
%e A316586 ...
%Y A316586 Cf. A316564, A316584.
%K A316586 nonn,tabl,mult
%O A316586 1,5
%A A316586 _Andrew Howroyd_, Jul 07 2018