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

1,3

Comments

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

See A352550 for comments and PARI code.

Links

Table of n, a(n) for n=1..96.

Crossrefs

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

Sequence in context: A130071 A321373 A305615 * A335060 A333058 A084348

Adjacent sequences: A038537 A038538 A038539 * A038541 A038542 A038543

Keyword

nonn,mult

Author

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

Extensions

Edited by M. F. Hasler, Feb 18 2022

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

Status

approved