Permanent of "coprime?" matrix.

Terms

a(0) =1a(1) =1a(2) =3a(3) =4a(4) =28a(5) =16a(6) =256a(7) =324a(8) =3600a(9) =3600a(10) =129744a(11) =63504a(12) =3521232a(13) =3459600a(14) =60891840a(15) =91240704a(16) =8048712960a(17) =3554067456a(18) =425476094976a(19) =320265446400