Partial sums of A000111.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =10a(5) =26a(6) =87a(7) =359a(8) =1744a(9) =9680a(10) =60201a(11) =413993a(12) =3116758a(13) =25485014a(14) =224845995a(15) =2128603307a(16) =21520115452a(17) =231385458428