INVERT transform of phi(n), A000010.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =11a(5) =26a(6) =57a(7) =131a(8) =296a(9) =669a(10) =1515a(11) =3430a(12) =7765a(13) =17577a(14) =39790a(15) =90069a(16) =203897a(17) =461562a(18) =1044847a(19) =2365239a(20) =5354224a(21) =12120455a(22) =27437267a(23) =62110208a(24) =140599921a(25) =318278385a(26) =720492104a(27) =1630990029a(28) =3692099407a(29) =8357867190