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A284991
Triangle T(n,t) read by rows: the number of n X n {0,1} matrices with trace t where each row sum and each column sum is 4.
4
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 10, 20, 45, 44, 265, 1920, 6300, 13720, 20175, 18000, 7570, 357435, 2398900, 7499940, 14372820, 18433415, 15729000, 8171730, 1975560, 749649145, 4695264000, 13718863480, 24545693760, 29544855480, 24545693760, 13718863480, 4695264000, 749649145
OFFSET
0,18
EXAMPLE
0: 1
1: 0 0
2: 0 0 0
3: 0 0 0 0
4: 0 0 0 0 1
5: 1 0 10 20 45 44
6: 265 1920 6300 13720 20175 18000 7570
7: 357435 2398900 7499940 14372820 18433415 15729000 8171730 1975560
CROSSREFS
Cf. A058528 (row sums), A007105 (diagonal?), A139670 (symmetric matrices).
Sequence in context: A110804 A048063 A007927 * A327692 A269234 A160517
KEYWORD
nonn,tabl
AUTHOR
R. J. Mathar, Apr 07 2017
EXTENSIONS
More terms from Alois P. Heinz, Apr 09 2017
STATUS
approved