a(1)=1; thereafter, a(n+1) = 20*n^3 + 10*n.

Terms

a(0) =1a(1) =30a(2) =180a(3) =570a(4) =1320a(5) =2550a(6) =4380a(7) =6930a(8) =10320a(9) =14670a(10) =20100a(11) =26730a(12) =34680a(13) =44070a(14) =55020a(15) =67650a(16) =82080a(17) =98430a(18) =116820a(19) =137370a(20) =160200a(21) =185430a(22) =213180a(23) =243570a(24) =276720a(25) =312750a(26) =351780a(27) =393930a(28) =439320a(29) =488070