Powerful(1) numbers (A001694) which are the sum of distinct double factorials (A006882).

Terms

a(0) =1a(1) =4a(2) =8a(3) =9a(4) =16a(5) =25a(6) =27a(7) =49a(8) =64a(9) =72a(10) =108a(11) =121a(12) =125a(13) =128a(14) =169a(15) =392a(16) =400a(17) =432a(18) =441a(19) =500a(20) =512a(21) =961a(22) =968a(23) =972a(24) =1125a(25) =1331a(26) =1352a(27) =1444a(28) =3844a(29) =3888