A062558 Number of nonisomorphic cyclic subgroups of dihedral group with 2n elements.

2, 2, 3, 3, 3, 4, 3, 4, 4, 4, 3, 6, 3, 4, 5, 5, 3, 6, 3, 6, 5, 4, 3, 8, 4, 4, 5, 6, 3, 8, 3, 6, 5, 4, 5, 9, 3, 4, 5, 8, 3, 8, 3, 6, 7, 4, 3, 10, 4, 6, 5, 6, 3, 8, 5, 8, 5, 4, 3, 12, 3, 4, 7, 7, 5, 8, 3, 6, 5, 8, 3, 12, 3, 4, 7, 6, 5, 8, 3, 10, 6, 4, 3, 12, 5, 4, 5, 8, 3, 12, 5, 6, 5, 4, 5, 12, 3, 6, 7, 9, 3

Offset: 1

Author

Vladeta Jovovic, Jul 03 2001

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..1001

Crossrefs

Cf. A000005, A000045, A023645, A062249 (labeled case).

One more than A076984.

Programs

PARI

a(n) = numdiv(n) + (n % 2) \\ Michel Marcus, Jun 17 2013

Formula

a(n) = A000005(n) + A000035(n) = tau(n)+(n mod 2), where tau(n) = the number of divisors of n.