Expansion of Sum_{k>=0} (x * (2 + x^k))^k.

Terms

a(0) =1a(1) =2a(2) =5a(3) =8a(4) =20a(5) =32a(6) =77a(7) =128a(8) =288a(9) =518a(10) =1104a(11) =2048a(12) =4313a(13) =8192a(14) =16832a(15) =32848a(16) =66568a(17) =131072a(18) =264688a(19) =524288a(20) =1053737a(21) =2097824a(22) =4205568a(23) =8388608a(24) =16803744a(25) =33554442a(26) =67162112a(27) =134222336a(28) =268550704a(29) =536870912