Sum of divisors of twice square numbers.

Terms

a(0) =3a(1) =15a(2) =39a(3) =63a(4) =93a(5) =195a(6) =171a(7) =255a(8) =363a(9) =465a(10) =399a(11) =819a(12) =549a(13) =855a(14) =1209a(15) =1023a(16) =921a(17) =1815a(18) =1143a(19) =1953a(20) =2223a(21) =1995a(22) =1659a(23) =3315a(24) =2343a(25) =2745a(26) =3279a(27) =3591a(28) =2613a(29) =6045