%I #20 Mar 24 2020 22:30:43
%S 1,1,2,1,0,3,1,2,0,4,1,3,4,0,5,1,2,21,20,0,6,1,5,4,903,220,0,7,1,2,
%T 1555,6,2667,1220,0,8,1,7,3,9673655,12,7077,2420,0,9,1,2,889,4,
%U 187159211791705,42,113799,5060,0,10,1,3,4,2359,6,776119592182705,52,114681,13420,0,11
%N A(n,k) is the n-th number m such that m^2 divides k^m - 1 (or 0 if m does not exist); square array A(n,k), n>=1, k>=1, read by antidiagonals.
%e Square array A(n,k) begins:
%e 1, 1, 1, 1, 1, 1, ...
%e 2, 0, 2, 3, 2, 5, ...
%e 3, 0, 4, 21, 4, 1555, ...
%e 4, 0, 20, 903, 6, 9673655, ...
%e 5, 0, 220, 2667, 12, 187159211791705, ...
%e 6, 0, 1220, 7077, 42, 776119592182705, ...
%Y Columns k=1-24 give: A000027, A063524, A127103, A127104, A127105, A127106, A127107, A127102, A127101, A127100, A127092, A128405, A128393, A128394, A128395, A128396, A128397, A128398, A128399, A128400, A128401, A128402, A128403, A128404.
%Y Main diagonal gives A333502.
%Y Cf. A333432.
%K nonn,tabl
%O 1,3
%A _Seiichi Manyama_, Mar 24 2020