G.f.: exp( Sum_{n>=1} A064027(n)*x^n/n ), where A064027(n) = (-1)^n*Sum_{d|n}(-1)^d*d^2.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =10a(5) =18a(6) =32a(7) =59a(8) =106a(9) =181a(10) =305a(11) =518a(12) =867a(13) =1418a(14) =2301a(15) =3724a(16) =5966a(17) =9448a(18) =14862a(19) =23263a(20) =36165a(21) =55802a(22) =85609a(23) =130732a(24) =198574a(25) =299941a(26) =450946a(27) =675153a(28) =1006395a(29) =1493598