A169955 Number of tau-isomorphism classes of spherical bitrades with |T0| = n.

1, 0, 3, 1, 6, 9, 30, 51, 198, 470, 1623, 4830, 16070, 51948, 175047, 588120, 2015226, 6933048, 24123941, 84428820, 297753519

Offset: 4

Author

N. J. A. Sloane, Aug 01 2010

Keywords

• nonn

Links

• Ales Drapal, Carlo Hamalainen and Dan Rosendorf, An enumeration of spherical latin bitrades, arXiv:0907.1376 [math.CO], Sep 16 2009.
• Carlo Hamalainen, Enumeration of spherical bitrades, archive of C++ code, Sept 15, 2009.

Crossrefs

Cf. A007083, A167123.

Extensions

Offset corrected and a(4)-a(5) added by Hugo Pfoertner, Aug 11 2017