a(n) = 2*A002309(n).

Terms

a(0) =2a(1) =164a(2) =1414a(3) =6216a(4) =19338a(5) =48620a(6) =105742a(7) =206992a(8) =374034a(9) =634676a(10) =1023638a(11) =1583320a(12) =2364570a(13) =3427452a(14) =4842014a(15) =6689056a(16) =9060898a(17) =12062148a(18) =15810470a(19) =20437352a(20) =26088874a(21) =32926476a(22) =41127726a(23) =50887088a(24) =62416690a(25) =75947092a(26) =91728054a(27) =110029304a(28) =131141306a(29) =155376028