Euler transform of {1, primes}.

Terms

a(0) =1a(1) =3a(2) =6a(3) =14a(4) =27a(5) =58a(6) =109a(7) =216a(8) =402a(9) =760a(10) =1390a(11) =2550a(12) =4569a(13) =8178a(14) =14408a(15) =25280a(16) =43850a(17) =75685a(18) =129436a(19) =220226a(20) =371906a(21) =624840a(22) =1043178a(23) =1733108a(24) =2863422a(25) =4709222a(26) =7706800a(27) =12558213a(28) =20372860a(29) =32917707