a(n) = (7*n+1)*(7*n+6).

Terms

a(0) =6a(1) =104a(2) =300a(3) =594a(4) =986a(5) =1476a(6) =2064a(7) =2750a(8) =3534a(9) =4416a(10) =5396a(11) =6474a(12) =7650a(13) =8924a(14) =10296a(15) =11766a(16) =13334a(17) =15000a(18) =16764a(19) =18626a(20) =20586a(21) =22644a(22) =24800a(23) =27054a(24) =29406a(25) =31856a(26) =34404a(27) =37050a(28) =39794a(29) =42636