%I #6 May 29 2023 13:00:57
%S 1,3,1,4,1,1,7,3,1,1,6,2,1,1,1,12,5,3,1,1,1,8,3,2,1,1,1,1,15,7,3,3,1,
%T 1,1,1,13,5,4,2,1,1,1,1,1,18,8,4,3,3,1,1,1,1,1,12,5,3,2,2,1,1,1,1,1,1,
%U 28,13,8,5,3,3,1,1,1,1,1,1
%N Triangle read by rows: A051731 * A010766 as infinite lower triangular matrices.
%C Left column = sigma(n), A000203.
%C Row sums = A143356: (1, 4, 56, 12, 11, 23, 17,...).
%e First few rows of the triangle =
%e 1;
%e 3, 1;
%e 4, 1, 1;
%e 7, 3, 1, 1;
%e 6, 2, 1, 1, 1;
%e 12, 5, 3, 1, 1, 1;
%e 8, 3, 2, 1, 1, 1, 1;
%e 15, 7, 3, 3, 1, 1, 1, 1;
%e ...
%Y Cf. A000203, A010766, A051731, A143356.
%K nonn,tabl
%O 1,2
%A _Gary W. Adamson_, Aug 10 2008
%E a(72) split by _Georg Fischer_, May 29 2023