

A228167


Irregular triangle read by rows: T(n,k) is the number of binary pattern classes in the (8,n)rectangular grid with k '1's and (8nk) '0's: two patterns are in the same class if one of them can be obtained by a reflection or 180degree rotation of the other.


24



1, 1, 4, 16, 28, 38, 28, 16, 4, 1, 1, 4, 36, 140, 476, 1092, 2044, 2860, 3270, 2860, 2044, 1092, 476, 140, 36, 4, 1, 1, 8, 84, 536, 2770, 10808, 34116, 87144, 185071, 328208, 492392, 625968, 678524, 625968, 492392, 328208, 185071, 87144, 34116, 10808, 2770, 536, 84, 8, 1
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OFFSET

0,3


COMMENTS

The length of row n is 8*n+1.
Sum of rows (see example) gives A225832.
Also the number of equivalence classes of ways of placing k 1 X 1 tiles in an n X 8 rectangle under all symmetry operations of the rectangle.  Christopher Hunt Gribble, Feb 28 2014


LINKS



EXAMPLE

Irregular triangle:
1
1 4 16 28 38 28 16 4 1
1 4 36 140 476 1092 2044 2860 3270 2860 2044 1092 ...
1 8 84 536 2770 10808 34116 87144 185071 328208 492392 625968 678524 625968 492392 ...


CROSSREFS



KEYWORD

nonn,tabf


AUTHOR



EXTENSIONS



STATUS

approved



