A131899 - OEIS

%I #6 Mar 04 2022 02:06:05

%S 1,2,3,3,2,5,4,2,3,7,5,2,3,4,9,6,2,3,4,5,11,7,2,3,4,5,6,13,8,2,3,4,5,

%T 6,7,15,9,2,3,4,5,6,7,8,17,10,2,3,4,5,6,7,8,9,19

%N A002260 + A131821 - A000012.

%C Row sums = A052905: (1, 5, 10, 16, 23, ...)

%F A002260 + A131821 - A000012 as infinite lower triangular matrices.

%e First few rows of the triangle:

%e   1;

%e   2,  3;

%e   3,  2,  5;

%e   4,  2,  3,  7;

%e   5,  2,  3,  4,  9;

%e   6,  2,  3,  4,  5, 11;

%e   7,  2,  3,  4,  5,  6, 13;

%e   ...

%Y Cf. A002260, A131821, A052905.

%K nonn,tabl

%O 0,2

%A _Gary W. Adamson_, Jul 25 2007