Number of 2 X 2 matrices with all terms in {-n,...,0,...,n} and (sum of terms) = permanent.

Terms

a(0) =1a(1) =21a(2) =52a(3) =172a(4) =268a(5) =428a(6) =588a(7) =812a(8) =1004a(9) =1324a(10) =1580a(11) =1900a(12) =2252a(13) =2668a(14) =2988a(15) =3532a(16) =3916a(17) =4460a(18) =5004a(19) =5548a(20) =6028a(21) =6764a(22) =7308a(23) =8044a(24) =8716a(25) =9548a(26) =10156a(27) =11116a(28) =11852a(29) =12620