

A112426


Number of connected simple graphs with n vertices, n+6 edges, and vertex degrees no more than 4.


7



0, 0, 0, 0, 0, 1, 9, 134, 1714, 18436, 167703, 1327240, 9372119, 60324933
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OFFSET

1,7


COMMENTS

Distribution of carbon skeletons. See the paper by Hendrikson and Parks for details. If n=6 the number of 7cyclic skeletons is 1. If n=7 the number of 7cyclic skeletons is 9. If n=10 the number of 7cyclic skeletons is 18436.  Parthasarathy Nambi, Jan 05 2007


LINKS

Table of n, a(n) for n=1..14.
J. B. Hendrickson and C. A. Parks, Generation and Enumeration of Carbon skeletons, J. Chem. Inf. Comput. Sci., 31 (1991), 101107. See Table 2, column 7 on page 103.
Michael A. Kappler, GENSMI: Exhaustive Enumeration of Simple Graphs [gives different numbers for n >= 10].


PROG

(nauty/bash)
for n in {6..13}; do geng c D4 ${n} $((n+6)):$((n+6)) u; done # Andrey Zabolotskiy, Nov 24 2017


CROSSREFS

The analogs for n+k edges with k = 1, 0, ..., 7 are: A000602, A036671, A112410, A112619, A112408, A112424, A112425, this sequence, A112442. Cf. A121941.
Sequence in context: A110273 A082760 A268654 * A213688 A163200 A279975
Adjacent sequences: A112423 A112424 A112425 * A112427 A112428 A112429


KEYWORD

nonn


AUTHOR

Jonathan Vos Post, Dec 21 2005


EXTENSIONS

New name, offset corrected, and a(10)a(13) corrected by Andrey Zabolotskiy, Nov 24 2017


STATUS

approved



