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A293073
Number of matchings in the n-cocktail party graph.
0
1, 7, 51, 513, 6345, 93255, 1584555, 30524865, 656843985, 15605162055, 405495737955, 11435339115585, 347722239169305, 11337916544369415, 394530748734397275, 14590576590956791425, 571378543704076133025, 23617402334089770781575
OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Cocktail Party Graph
Eric Weisstein's World of Mathematics, Independent Edge Set
Eric Weisstein's World of Mathematics, Matching
MATHEMATICA
RecurrenceTable[{4 (1 + n) (2 + n) a[n] + (4 + 10 n + 4 n^2) a[1 + n] + (-9 - 4 n) a[2 + n] + a[3 + n] == 0, a[1] == 1, a[2] == 7, a[3] == 51}, a, {n, 20}]
CROSSREFS
Sequence in context: A230883 A304939 A352358 * A368286 A081216 A198087
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Sep 30 2017
STATUS
approved