Number of similar sublattices of Z^4 of index n^2.

Terms

a(0) =1a(1) =3a(2) =8a(3) =3a(4) =12a(5) =24a(6) =16a(7) =3a(8) =41a(9) =36a(10) =24a(11) =24a(12) =28a(13) =48a(14) =96a(15) =3a(16) =36a(17) =123a(18) =40a(19) =36a(20) =128a(21) =72a(22) =48a(23) =24a(24) =97a(25) =84a(26) =176a(27) =48a(28) =60a(29) =288