A060689 Number of nonabelian groups of order n.

0, 0, 0, 0, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 9, 0, 3, 0, 3, 1, 1, 0, 12, 0, 1, 2, 2, 0, 3, 0, 44, 0, 1, 0, 10, 0, 1, 1, 11, 0, 5, 0, 2, 0, 1, 0, 47, 0, 3, 0, 3, 0, 12, 1, 10, 1, 1, 0, 11, 0, 1, 2, 256, 0, 3, 0, 3, 0, 3, 0, 44, 0, 1, 1, 2, 0, 5, 0, 47, 10, 1, 0, 13, 0, 1, 0, 9, 0, 8, 0, 2

Offset: 1

Author

Ahmed Fares (ahmedfares(AT)my-deja.com), Apr 19 2001

Keywords

• nonn

Comments

a(n) = 0 iff n belongs to sequence A051532.

Examples

			a(6) = 1 because the only non-Abelian group of order 6 is the symmetric group S_3.
		

Links

• Andrey Zabolotskiy, Table of n, a(n) for n = 1..2047 [terms up to a(2015) from T. D. Noe, a(1024) corrected by Andrey Zabolotskiy]
• Index entries for sequences related to groups

Crossrefs

Cf. A000001, A000688.

Programs

Mathematica

Table[FiniteGroupCount[n]-FiniteAbelianGroupCount[n],{n,6!}] (* Vladimir Joseph Stephan Orlovsky, Feb 12 2010 *)

Formula

a(n) = A000001(n) - A000688(n).

Extensions

Corrected by Avi Peretz (njk(AT)netvision.net.il), Apr 21 2001