A004077 Number of extended Skolem sequences of order n.
2, 2, 6, 22, 48, 160, 636, 3556, 19488, 95872, 594320, 4459888, 32131648, 227072544, 1875064880, 17851780784, 165367171136, 1506506453568, 15540217445728, 179708231523680, 2034547787823488, 22716589497430656
Offset: 1
References
- CRC Handbook of Combinatorial Designs, 1996, p. 460.
Links
- Jeppe Winther Larsen, Counting the Skolem sequences using inclusion-exclusion, 2009
Extensions
a(15)-a(18) from Jeppe Winther Larsen (jwl(AT)itu.dk), Oct 12 2009
a(19)-a(21) from Fausto A. C. Cariboni, Apr 19 2017
a(22) from Fausto A. C. Cariboni, May 07 2017