A006536 Switching classes of digraphs.

2, 6, 38, 684, 50224, 13946352, 14061131152, 50947324188128, 666754350781269760, 31763991166456912086656, 5550343429517595744902558208, 3581353054755185129132443153728000

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• nice

References

• R. C. Read, personal communication.
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• R. C. Read, Letter to N. J. A. Sloane, Oct. 29, 1976

Crossrefs

Cf. A002854, A049313.

Extensions

More terms from Vladeta Jovovic, Jul 22 2000