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A007719 Number of independent polynomial invariants of symmetric matrix of order n. 2
1, 2, 4, 11, 30, 95, 328, 1211, 4779, 19902, 86682, 393072, 1847264, 8965027, 44814034, 230232789, 1213534723, 6552995689, 36207886517, 204499421849, 1179555353219, 6942908667578, 41673453738272, 254918441681030, 1588256152307002, 10073760672179505 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Also, number of connected multigraphs with n edges (allowing loops) and any number of nodes.

LINKS

Table of n, a(n) for n=0..25.

R. J. Mathar, Statistics on Small Graphs, arXiv:1709.09000 (2017) Table 63.

FORMULA

Inverse Euler transform of A007717.

CROSSREFS

Cf. A002905, A007717, A076864, A191970.

Sequence in context: A148153 A148154 A148155 * A148156 A148157 A141268

Adjacent sequences:  A007716 A007717 A007718 * A007720 A007721 A007722

KEYWORD

nonn,nice

AUTHOR

Colin Mallows

EXTENSIONS

a(0)=1 added by Alberto Tacchella, Jun 20 2011

a(7)-a(25) from Franklin T. Adams-Watters, Jun 21 2011

STATUS

approved

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Last modified November 19 03:59 EST 2017. Contains 294912 sequences.