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

1,4

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

Table of n, a(n) for n=1..25.

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

Formula

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

Crossrefs

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

Sequence in context: A188229 A277739 A098644 * A132105 A019021 A110505

Adjacent sequences: A182319 A182320 A182321 * A182323 A182324 A182325

Keyword

nonn,easy

Author

Robert A. Russell, Apr 24 2012

Status

approved