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a(n)=det(M_n) where M_n is the n X n matrix m(i,j)=i^j*j^i.
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%I #11 Apr 19 2024 09:19:31

%S 1,12,4284,84720384,148993369113600,34155172566092379340800,

%T 1406681240638328150516203644518400,

%U 13722109275339434419337247034130459935742361600

%N a(n)=det(M_n) where M_n is the n X n matrix m(i,j)=i^j*j^i.

%F Conjecture: lim_{n->oo} a(n)^(1/n^2)/n = 2*exp(-3/2). - _Vaclav Kotesovec_, Apr 19 2024

%t Table[Det[Table[i^j j^i,{i,n},{j,n}]],{n,8}] (* _Harvey P. Dale_, Jun 26 2021 *)

%o (PARI) for(n=1,10,print1(matdet(matrix(n,n,i,j,i^j*j^i)),","))

%Y Cf. A071409, A071410, A169657.

%K easy,nonn

%O 1,2

%A _Benoit Cloitre_, May 30 2002