A204252 Permanent of the n-th principal submatrix of A201208 (in square format).
1, 5, 18, 132, 876, 8820, 85392, 1106496, 14057280, 223560000, 3513456000, 66305952000, 1241430624000, 27127003680000, 589395356928000, 14638710417408000, 362021985626112000, 10073602372700160000, 279369787588448256000, 8609476463579013120000, 264609942011693752320000
Offset: 1
Keywords
Links
- Vaclav Kotesovec, Table of n, a(n) for n = 1..30
Programs
-
Maple
a:= n-> LinearAlgebra[Permanent](Matrix(n, (i, j)-> 1+irem(i+j, 2))): seq(a(n), n=1..20); # Alois P. Heinz, Apr 23 2025
-
Mathematica
f[i_, j_] := 1 + Mod[i + j, 2]; m[n_] := Table[f[i, j], {i, 1, n}, {j, 1, n}] TableForm[m[8]] (* 8x8 principal submatrix *) Flatten[Table[f[i, n + 1 - i], {n, 1, 12}, {i, 1, n}]] (* A201208 in square format *) Permanent[m_] := With[{a = Array[x, Length[m]]}, Coefficient[Times @@ (m.a), Times @@ a]]; Table[Permanent[m[n]], {n, 1, 20}] (* A204252 *) -
PARI
a(n) = {matpermanent(matrix(n, n, i, j, 1 + (i+j)%2))}; for(n=1, 25, print1(a(n), ", ")) \\ Vaclav Kotesovec, Apr 21 2025
Extensions
a(20)-a(21) from Pontus von Brömssen, Mar 03 2024