Partial sums of A006206.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =6a(5) =8a(6) =12a(7) =17a(8) =25a(9) =36a(10) =54a(11) =79a(12) =119a(13) =177a(14) =267a(15) =402a(16) =612a(17) =928a(18) =1420a(19) =2170a(20) =3334a(21) =5125a(22) =7911a(23) =12216a(24) =18926a(25) =29346a(26) =45610a(27) =70960a(28) =110610a(29) =172577