Exponential convolution of odd numbers (A005408) with themselves.

Terms

a(0) =1a(1) =6a(2) =28a(3) =104a(4) =336a(5) =992a(6) =2752a(7) =7296a(8) =18688a(9) =46592a(10) =113664a(11) =272384a(12) =643072a(13) =1499136a(14) =3457024a(15) =7897088a(16) =17891328a(17) =40239104a(18) =89915392a(19) =199753728a(20) =441450496a(21) =970981376a(22) =2126512128a(23) =4638900224a(24) =10083106816a(25) =21843935232a(26) =47177531392a(27) =101602820096a(28) =218238025728