A080850 Number triangle related to a problem of Knuth.

1, 1, 1, 1, 2, 1, 2, 3, 3, 1, 5, 5, 6, 4, 1, 11, 10, 11, 10, 5, 1, 22, 21, 21, 21, 15, 6, 1, 43, 43, 42, 42, 36, 21, 7, 1, 85, 86, 85, 84, 78, 57, 28, 8, 1, 170, 171, 171, 169, 162, 135, 85, 36, 9, 1, 341, 341, 342, 340, 331, 297, 220, 121, 45, 10, 1, 683, 682, 683, 671, 628, 517

Offset: 1

Author

Paul Barry, Feb 20 2003

Keywords

• easy
• nonn
• tabl

Comments

In lower-triangular form, the columns are the binomial transforms of the sequences with g.f. x^(k-1)/(1-x^3). The first three columns are A024493, A024494, A024495.

Examples

			Rows are {1}, {1,1}, {1,2,1}, {2,3,3,1}, {5,5,6,4,1}, {11,10,11,10,5,1}...
		

Formula

T(n, 1) = A024493(n). T(n, k)=0, k>n, T(n, n)=1. T(n, k) = T(n-1, k-1)+T(n-1, k).