Partial sums of A006899.

Terms

a(0) =1a(1) =3a(2) =6a(3) =10a(4) =18a(5) =27a(6) =43a(7) =70a(8) =102a(9) =166a(10) =247a(11) =375a(12) =618a(13) =874a(14) =1386a(15) =2115a(16) =3139a(17) =5187a(18) =7374a(19) =11470a(20) =18031a(21) =26223a(22) =42607a(23) =62290a(24) =95058a(25) =154107a(26) =219643a(27) =350715a(28) =527862a(29) =790006