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A351020
Maximal permanent of an n X n symmetric Toeplitz matrix using the integers 1 to n.
9
1, 1, 5, 64, 1650, 66731, 3968777, 323676148, 34890266414, 4780256317586, 814873637329516, 168491370685328792
OFFSET
0,3
EXAMPLE
a(3) = 64:
2 3 1
3 2 3
1 3 2
a(4) = 1650:
3 4 2 1
4 3 4 2
2 4 3 4
1 2 4 3
a(5) = 66731:
3 5 4 2 1
5 3 5 4 2
4 5 3 5 4
2 4 5 3 5
1 2 4 5 3
PROG
(Python)
from itertools import permutations
from sympy import Matrix
def A351020(n): return 1 if n == 0 else max(Matrix([p[i:0:-1]+p[0:n-i] for i in range(n)]).per() for p in permutations(range(1, n+1))) # Chai Wah Wu, Jan 31 2022
CROSSREFS
Cf. A204235, A307783, A350938, A351019 (minimal).
Sequence in context: A196304 A061684 A061698 * A238631 A220557 A266962
KEYWORD
nonn,hard,more
AUTHOR
Stefano Spezia, Jan 29 2022
EXTENSIONS
a(9) from Alois P. Heinz, Jan 31 2022
a(10)-a(11) from Lucas A. Brown, Sep 06 2022
STATUS
approved