This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A351019 #23 Oct 13 2022 06:50:26 %S A351019 1,1,5,36,480,9991,296913,12099604,637590728,43090005714, %T A351019 3550491371994,359557627057876 %N A351019 Minimal permanent of an n X n symmetric Toeplitz matrix using the integers 1 to n. %H A351019 Lucas A. Brown, <a href="https://github.com/lucasaugustus/oeis/blob/main/A351019%2B20.sage">A351019+20.sage</a> %H A351019 Wikipedia, <a href="http://en.wikipedia.org/wiki/Toeplitz_matrix">Toeplitz Matrix</a> %e A351019 a(3) = 36: %e A351019 2 1 3 %e A351019 1 2 1 %e A351019 3 1 2 %e A351019 a(4) = 480: %e A351019 2 1 3 4 %e A351019 1 2 1 3 %e A351019 3 1 2 1 %e A351019 4 3 1 2 %e A351019 a(5) = 9991: %e A351019 3 1 2 4 5 %e A351019 1 3 1 2 4 %e A351019 2 1 3 1 2 %e A351019 4 2 1 3 1 %e A351019 5 4 2 1 3 %o A351019 (Python) %o A351019 from itertools import permutations %o A351019 from sympy import Matrix %o A351019 def A351019(n): return 1 if n == 0 else min(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 %Y A351019 Cf. A204235, A307783, A350937, A351020 (maximal). %K A351019 nonn,hard,more %O A351019 0,3 %A A351019 _Stefano Spezia_, Jan 29 2022 %E A351019 a(9) from _Alois P. Heinz_, Jan 31 2022 %E A351019 a(10)-a(11) from _Lucas A. Brown_, Sep 06 2022