Number of 2 X 2 matrices M of positive integers such that permanent(M) < n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =5a(5) =13a(6) =27a(7) =47a(8) =75a(9) =112a(10) =156a(11) =214a(12) =278a(13) =358a(14) =444a(15) =552a(16) =660a(17) =796a(18) =930a(19) =1099a(20) =1259a(21) =1457a(22) =1649a(23) =1885a(24) =2101a(25) =2377a(26) =2623a(27) =2933a(28) =3221a(29) =3569