A278927 a(n) = permanent M_n where M_n is the n X n matrix m(i,j) = 2*i + j.

1, 3, 38, 1116, 59392, 5004720, 613252320, 103050420480, 22752244279296, 6388491978086400, 2223423557203968000, 939489529945565491200, 473789563269835667374080, 281112352557447776249364480, 193857685859605294233907200000, 153758529080702011472247521280000

Offset: 0

Author

Vaclav Kotesovec, Dec 01 2016

Keywords

• nonn

Links

• Vaclav Kotesovec, Table of n, a(n) for n = 0..36

Crossrefs

Cf. A204249.

Programs

Maple

with(LinearAlgebra):
a:= n-> `if`(n=0, 1, Permanent(Matrix(n, (i, j)-> 2*i+j))):
seq(a(n), n=0..16);

Mathematica

Flatten[{1, Table[Permanent[Table[2*i+j, {i, 1, n}, {j, 1, n}]], {n, 1, 15}]}]

PARI

{a(n) = matpermanent(matrix(n, n, i, j, 2*i+j))}
for(n=0, 20, print1(a(n), ", ")) \\ Vaclav Kotesovec, Dec 21 2018

Formula

a(n) ~ c * d^n * n!^2 / sqrt(n), where d = 3.63208011334048289... and c = 1.47836065972078...