OFFSET
1,3
COMMENTS
Induced cycles are sometimes called chordless cycles (but some definitions require chordless cycles to have a cycle length of at least 4). See A070968 for the version that excludes triangles.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..100
Eric Weisstein's World of Mathematics, Rook Graph.
Wikipedia, Cycle (graph theory).
FORMULA
PROG
(PARI) a(n) = 2*n*binomial(n, 3) + sum(k=2, n, binomial(n, k)^2 * k! * (k-1)!)/2
CROSSREFS
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Feb 24 2023
STATUS
approved