%I #2 Mar 30 2012 17:25:32
%S 1,2,2,2,2,2,3,4,2,2,2,2,2,2,2,4,6,4,2,2,2,2,2,2,2,2,2,2,4,6,4,4,2,2,
%T 2,2,3,4,4,2,2,2,2,2,2,4,6,4,4,4,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,6,10,
%U 8,6,4,4,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2
%N Triangle read by rows, A051731 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's).
%C Left column = d(n), A000005: (1, 2, 2, 3, 2, 4, 2,...).
%C Prime rows have all 2's.
%C Row sums = A129235: (1, 4, 6, 11, 10, 10,...).
%F Triangle read by rows, A051731 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's), i.e. (1; 1,2; 1,2,2;...), 1<=k<=n A051731 = the inverse Mobius transform.
%e First few rows of the triangle =
%e 1;
%e 2, 2;
%e 2, 2, 2;
%e 3, 4, 2, 2;
%e 2, 2, 2, 2, 2;
%e 4, 6, 4, 2, 2, 2;
%e 2, 2, 2, 2, 2, 2, 2;
%e ...
%Y Cf. A129235, A000005, A051731.
%K nonn,tabl
%O 1,2
%A _Gary W. Adamson_, Aug 26 2008