Spiral tiling numbers.

Terms

a(0) =3a(1) =4a(2) =6a(3) =12a(4) =36a(5) =42a(6) =48a(7) =192a(8) =294a(9) =324a(10) =768a(11) =2058a(12) =2916a(13) =3072a(14) =12288a(15) =14406a(16) =26244a(17) =49152a(18) =100842a(19) =196608a(20) =236196a(21) =705894a(22) =786432a(23) =2125764a(24) =3145728a(25) =4941258a(26) =12582912a(27) =19131876a(28) =34588806a(29) =50331648