a(n) = (117*n^2 - 99*n + 2)/2.

Terms

a(0) =1a(1) =10a(2) =136a(3) =379a(4) =739a(5) =1216a(6) =1810a(7) =2521a(8) =3349a(9) =4294a(10) =5356a(11) =6535a(12) =7831a(13) =9244a(14) =10774a(15) =12421a(16) =14185a(17) =16066a(18) =18064a(19) =20179a(20) =22411a(21) =24760a(22) =27226a(23) =29809a(24) =32509a(25) =35326a(26) =38260a(27) =41311a(28) =44479a(29) =47764