Number of regions in a "frame" of size n X n (see Comments for definition).

Terms

a(0) =4a(1) =56a(2) =208a(3) =496a(4) =1016a(5) =1784a(6) =2984a(7) =4656a(8) =6968a(9) =9944a(10) =13976a(11) =18928a(12) =25360a(13) =33128a(14) =42488a(15) =53600a(16) =67232a(17) =82904a(18) =101744a(19) =123232a(20) =147896a(21) =175784a(22) =208296a(23) =244416a(24) =285600a(25) =331352a(26) =382608a(27) =439008a(28) =502776a(29) =571912