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
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Sep 30 2017
STATUS
approved