|
|
A268363
|
|
Number of n X 2 arrays containing 2 copies of 0..n-1 with row sums equal.
|
|
5
|
|
|
1, 1, 4, 12, 96, 480, 5760, 40320, 645120, 5806080, 116121600, 1277337600, 30656102400, 398529331200, 11158821273600, 167382319104000, 5356234211328000, 91055981592576000, 3278015337332736000, 62282291409321984000, 2491291656372879360000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
Some solutions for n=5
..3..1....1..3....4..0....0..4....0..4....4..0....4..0....4..0....2..2....1..3
..1..3....2..2....3..1....3..1....2..2....3..1....1..3....2..2....0..4....0..4
..0..4....0..4....0..4....2..2....1..3....1..3....0..4....1..3....3..1....4..0
..0..4....0..4....2..2....1..3....4..0....0..4....2..2....0..4....4..0....3..1
..2..2....3..1....1..3....0..4....1..3....2..2....1..3....3..1....3..1....2..2
|
|
MATHEMATICA
|
|
|
PROG
|
(Magma) [2^Floor(n/2)*Factorial(n): n in [0..25]]; // G. C. Greubel, Mar 08 2022
(Sage) [2^(n//2)*factorial(n) for n in (0..25)] # G. C. Greubel, Mar 08 2022
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|