Conway-Guy sequence: a(n + 1) = 2a(n) - a(n - floor( 1/2 + sqrt(2n) )).

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =7a(5) =13a(6) =24a(7) =44a(8) =84a(9) =161a(10) =309a(11) =594a(12) =1164a(13) =2284a(14) =4484a(15) =8807a(16) =17305a(17) =34301a(18) =68008a(19) =134852a(20) =267420a(21) =530356a(22) =1051905a(23) =2095003a(24) =4172701a(25) =8311101a(26) =16554194a(27) =32973536a(28) =65679652a(29) =130828948