a(n) = 2*A000447(n).

Terms

a(0) =0a(1) =2a(2) =20a(3) =70a(4) =168a(5) =330a(6) =572a(7) =910a(8) =1360a(9) =1938a(10) =2660a(11) =3542a(12) =4600a(13) =5850a(14) =7308a(15) =8990a(16) =10912a(17) =13090a(18) =15540a(19) =18278a(20) =21320a(21) =24682a(22) =28380a(23) =32430a(24) =36848a(25) =41650a(26) =46852a(27) =52470a(28) =58520a(29) =65018