Partial sums of A007694.

Terms

a(0) =1a(1) =3a(2) =7a(3) =13a(4) =21a(5) =33a(6) =49a(7) =67a(8) =91a(9) =123a(10) =159a(11) =207a(12) =261a(13) =325a(14) =397a(15) =493a(16) =601a(17) =729a(18) =873a(19) =1035a(20) =1227a(21) =1443a(22) =1699a(23) =1987a(24) =2311a(25) =2695a(26) =3127a(27) =3613a(28) =4125a(29) =4701