A131844 - OEIS

%I #16 Apr 18 2024 15:32:34

%S 1,4,4,7,1,7,10,1,1,10,13,1,1,1,13,16,1,1,1,1,16,19,1,1,1,1,1,19,22,1,

%T 1,1,1,1,1,22,25,1,1,1,1,1,1,1,25,28,1,1,1,1,1,1,1,1,28,31,1,1,1,1,1,

%U 1,1,1,1,31,34,1,1,1,1,1,1,1,1,1,1,34,37,1,1,1,1,1,1,1,1,1,1,1,37,40,1,1,1,1,1,1,1,1,1,1,1,1,40

%N 3*A131821 - 2.

%C Row sums = A016993, (7n + 1): (1, 8, 15, 22, 29, ...).

%F 3*A131821 - 2 as infinite lower triangular matrices.

%F Infinite lower triangular matrix, (3n + 1): (1, 4, 7, 10, ...) as right and left borders and the rest 1's.

%e First few rows of the triangle:

%e    1;

%e    4,  4;

%e    7,  1,  7;

%e   10,  1,  1, 10;

%e   13,  1,  1,  1, 13;

%e   16,  1,  1,  1,  1, 16;

%e   ...

%Y Cf. A131821, A016993.

%K nonn,tabl

%O 0,2

%A _Gary W. Adamson_, Jul 22 2007

%E More terms from _Russ Cox_, Apr 18 2024