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Triangle read by rows, A051731 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's).
1

%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