a(n) = (11*n^2 + 19*n + 10)/2.

Terms

a(0) =5a(1) =20a(2) =46a(3) =83a(4) =131a(5) =190a(6) =260a(7) =341a(8) =433a(9) =536a(10) =650a(11) =775a(12) =911a(13) =1058a(14) =1216a(15) =1385a(16) =1565a(17) =1756a(18) =1958a(19) =2171a(20) =2395a(21) =2630a(22) =2876a(23) =3133a(24) =3401a(25) =3680a(26) =3970a(27) =4271a(28) =4583a(29) =4906