A038540 a(n) = number of modules with n elements over the ring of integers in the real quadratic field of discriminant 40.

1, 1, 2, 2, 1, 2, 0, 3, 5, 1, 0, 4, 2, 0, 2, 5, 0, 5, 0, 2, 0, 0, 0, 6, 2, 2, 10, 0, 0, 2, 2, 7, 0, 0, 0, 10, 2, 0, 4, 3, 2, 0, 2, 0, 5, 0, 0, 10, 1, 2, 0, 4, 2, 10, 0, 0, 0, 0, 0, 4, 0, 2, 0, 11, 2, 0, 2, 0, 0, 0, 2, 15, 0, 2, 4, 0, 0, 4, 2, 5, 20, 2, 2, 0, 0, 2, 0, 0, 2, 5, 0, 0, 4, 0, 0, 14

Offset: 1

Author

Paolo Dominici (pl.dm(AT)libero.it)

Keywords

• nonn
• mult

Comments

Equivalently, number of modules with n elements over ring Z[sqrt(10)].

See A352550 for comments and PARI code.

Crossrefs

Cf. A038540, A038541, A248107, A352550-A352567.

Extensions

Edited by M. F. Hasler, Feb 18 2022

Revised by N. J. A. Sloane, Mar 21 2022