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A319526 Square array read by antidiagonals upwards: T(n,k) = sigma(n*k), n >= 1, k >= 1.

%I A319526 #33 Jan 08 2019 08:39:00
%S A319526 1,3,3,4,7,4,7,12,12,7,6,15,13,15,6,12,18,28,28,18,12,8,28,24,31,24,
%T A319526 28,8,15,24,39,42,42,39,24,15,13,31,32,60,31,60,32,31,13,18,39,60,56,
%U A319526 72,72,56,60,39,18,12,42,40,63,48,91,48,63,40,42,12,28,36,72,91,90,96,96,90,91,72,36,28
%N A319526 Square array read by antidiagonals upwards: T(n,k) = sigma(n*k), n >= 1, k >= 1.
%H A319526 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A319526 T(n,k) = A000203(n*k).
%F A319526 T(n,k) = A000203(A003991(n,k)).
%e A319526 The corner of the square array begins:
%e A319526 A000203:    1,   3,   4,   7,   6,  12,   8,  15,  13,  18,  12,  28, ...
%e A319526 A062731:    3,   7,  12,  15,  18,  28,  24,  31,  39,  42,  36,  60, ...
%e A319526 A144613:    4,  12,  13,  28,  24,  39,  32,  60,  40,  72,  48,  91, ...
%e A319526 A193553:    7,  15,  28,  31,  42,  60,  56,  63,  91,  90,  84, 124, ...
%e A319526 A283118:    6,  18,  24,  42,  31,  72,  48,  90,  78,  93,  72, 168, ...
%e A319526 A224613:   12,  28,  39,  60,  72,  91,  96, 124, 120, 168, 144, 195, ...
%e A319526 A283078:    8,  24,  32,  56,  48,  96,  57, 120, 104, 144,  96, 224, ...
%e A319526 A283122:   15,  31,  60,  63,  90, 124, 120, 127, 195, 186, 180, 252, ...
%e A319526 A283123:   13,  39,  40,  91,  78, 120, 104, 195, 121, 234, 156, 280, ...
%e A319526 ...
%t A319526 Table[DivisorSigma[1, # k] &[m - k + 1], {m, 12}, {k, m}] // Flatten (* _Michael De Vlieger_, Dec 31 2018 *)
%Y A319526 First 9 rows (also first 9 columns) are A000203, A062731, A144613, A193553, A283118, A224613, A283078, A283122, A283123.
%Y A319526 Main diagonal gives A065764.
%Y A319526 Cf. A000203, A003991, A216626, A319073.
%K A319526 nonn,tabl
%O A319526 1,2
%A A319526 _Omar E. Pol_, Sep 25 2018