a(0) = 1, a(1) = 1, a(n) = a(n-1) - a(n-2) + n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =6a(5) =7a(6) =7a(7) =7a(8) =8a(9) =10a(10) =12a(11) =13a(12) =13a(13) =13a(14) =14a(15) =16a(16) =18a(17) =19a(18) =19a(19) =19a(20) =20a(21) =22a(22) =24a(23) =25a(24) =25a(25) =25a(26) =26a(27) =28a(28) =30a(29) =31