a(n) = (n+1)^3 - n^2.

Terms

a(0) =1a(1) =7a(2) =23a(3) =55a(4) =109a(5) =191a(6) =307a(7) =463a(8) =665a(9) =919a(10) =1231a(11) =1607a(12) =2053a(13) =2575a(14) =3179a(15) =3871a(16) =4657a(17) =5543a(18) =6535a(19) =7639a(20) =8861a(21) =10207a(22) =11683a(23) =13295a(24) =15049a(25) =16951a(26) =19007a(27) =21223a(28) =23605a(29) =26159