|
Search: id:A057818
|
|
|
| A057818 |
|
Number of factorable (see A057765 for definition) subsets of a 2 X n uniform grid. |
|
+0
1
|
|
| 0, 1, 6, 33, 108, 345, 1014, 2865, 7464, 19791, 51286, 133249
(list; graph; listen)
|
|
|
OFFSET
|
1,3
|
|
|
EXAMPLE
|
There are six factorable subsets of
[___] namely [11_] [1_1] [_11] [111] [_11] [11_]
[___] ...... [22_] [2_2] [_22] [222] [22_] [_22], so a(3) = 6
(the numerals denote the elements of a particular translated copy).
|
|
CROSSREFS
|
See A057765 and A057750.
Sequence in context: A157872 A153127 A135526 this_sequence A063267 A082106 A073375
Adjacent sequences: A057815 A057816 A057817 this_sequence A057819 A057820 A057821
|
|
KEYWORD
|
nonn,nice,more
|
|
AUTHOR
|
John W. Layman (layman(AT)math.vt.edu), Nov 07 2000
|
|
|
Search completed in 0.002 seconds
|
