Partial sums of A004207.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =16a(5) =32a(6) =55a(7) =83a(8) =121a(9) =170a(10) =232a(11) =302a(12) =379a(13) =470a(14) =571a(15) =674a(16) =781a(17) =896a(18) =1018a(19) =1145a(20) =1282a(21) =1430a(22) =1591a(23) =1760a(24) =1945a(25) =2144a(26) =2362a(27) =2591a(28) =2833a(29) =3083