a(n) = (8*n + 6)^3.

Terms

a(0) =216a(1) =2744a(2) =10648a(3) =27000a(4) =54872a(5) =97336a(6) =157464a(7) =238328a(8) =343000a(9) =474552a(10) =636056a(11) =830584a(12) =1061208a(13) =1331000a(14) =1643032a(15) =2000376a(16) =2406104a(17) =2863288a(18) =3375000a(19) =3944312a(20) =4574296a(21) =5268024a(22) =6028568a(23) =6859000a(24) =7762392a(25) =8741816a(26) =9800344a(27) =10941048a(28) =12167000a(29) =13481272