OFFSET
0,3
COMMENTS
The length of row n is 6*n+1.
Sum of rows (see example) gives A225830.
This triangle is to A225828 as Losanitsch's triangle A034851 is to A005418, triangle A226048 to A225826, triangle A226290 to A225827, triangle A225812 to A225828, and triangle A228022 to A225829.
Also the number of equivalence classes of ways of placing k 1 X 1 tiles in an n X 6 rectangle under all symmetry operations of the rectangle. - Christopher Hunt Gribble, Apr 24 2015
LINKS
Yosu Yurramendi, María Merino, Rows n = 0..20 of irregular triangle, flattened
EXAMPLE
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
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Yosu Yurramendi, María Merino, Aug 14 2013
EXTENSIONS
Definition corrected by María Merino, May 22 2017
STATUS
approved