Closest integer to (Pi/4)*n^2.

Terms

a(0) =1a(1) =3a(2) =7a(3) =13a(4) =20a(5) =28a(6) =38a(7) =50a(8) =64a(9) =79a(10) =95a(11) =113a(12) =133a(13) =154a(14) =177a(15) =201a(16) =227a(17) =254a(18) =284a(19) =314a(20) =346a(21) =380a(22) =415a(23) =452a(24) =491a(25) =531a(26) =573a(27) =616a(28) =661a(29) =707