A182322 Number of simplicial 4-clusters with n cells. (Formerly M2679).

1, 1, 1, 3, 7, 30, 131, 795, 5152, 36800, 272093, 2077909, 16176607, 127996683, 1025727646, 8310377720, 67967600763, 560527576100, 4656993996246, 38949328897318, 327718211568300, 2772480181758683, 23571996461405321, 201327668784954950, 1726755218246463325

Offset: 1

Author

Robert A. Russell, Apr 24 2012

Keywords

• nonn
• easy

Comments

Some of the terms in the Hering article are in error, including the 6th, 8th and 9th.

References

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

Links

• F. Hering et al., The enumeration of stack polytopes and simplicial clusters, Discrete Math., 40 (1982), 203-217.

Crossrefs

This is the average of A007175 and A182299, both of which have Mathematica programs.

Formula

a(n) = (A007175(n) + A182299(n))/2.