A137679 - OEIS

%I #10 May 29 2023 11:25:44

%S 1,2,1,3,2,1,4,4,2,1,5,6,4,2,1,6,9,7,4,2,1,7,12,11,7,4,2,1,8,16,16,12,

%T 7,4,2,1,9,20,23,18,12,7,4,2,1,10,25,31,27,19,12,7,4,2,1,11,30,41,38,

%U 29,19,12,7,4,2,1,12,36,53,53,42,30,19,12,7,4,2,1

%N Triangle read by rows, A000012 * A008284.

%C Row sums = A026905: (1, 3, 6, 11, 18, 29, ...).

%C Rows tend to A000070 starting from the right: (1, 2, 4, 7, 12, 19, 30, ...).

%F A000012 * A008284 as infinite lower triangular matrices.

%e First few rows of the triangle:

%e   1;

%e   2,  1;

%e   3,  2,  1;

%e   4,  4,  2,  1;

%e   5,  6,  4,  2, 1;

%e   6,  9,  7,  4, 2, 1;

%e   7, 12, 11,  7, 4, 2, 1;

%e   8, 16, 16, 12, 7, 4, 2, 1;

%e   ...

%Y Cf. A000070, A008284, A026905.

%K nonn,tabl

%O 1,2

%A _Gary W. Adamson_, Feb 05 2008

%E a(38) = 20 corrected by _Georg Fischer_, May 29 2023