A228165 Irregular triangle read by rows: T(n,k) is the number of binary pattern classes in the (6,n)-rectangular grid with k '1's and (6n-k) '0's: two patterns are in same class if one of them can be obtained by a reflection or 180-degree rotation of the other.
1, 1, 3, 9, 10, 9, 3, 1, 1, 3, 21, 55, 135, 198, 246, 198, 135, 55, 21, 3, 1, 1, 6, 48, 218, 813, 2196, 4767, 8070, 11139, 12300, 11139, 8070, 4767, 2196, 813, 218, 48, 6, 1, 1, 6, 78, 506, 2706, 10626, 33814, 86526, 184239, 326876, 490908, 624036, 676732, 624036, 490908, 326876, 184239, 86526, 33814, 10626, 2706, 506, 78, 6, 1
Offset: 0
Examples
Irregular triangle: 1 1 3 9 10 9 3 1 1 3 21 55 135 198 246 198 135 55 21 3 1 1 6 48 18 813 2196 4767 8070 11139 12300 11139 8070 4767 2196 813 218 48 6 1
Links
- Yosu Yurramendi, María Merino, Rows n = 0..20 of irregular triangle, flattened
Extensions
Definition corrected by María Merino, May 22 2017
Comments