OFFSET
1,1
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..40
D. Wille, Enumeration of self-complementary structures, J. Comb. Theory B 25 (1978) 143-150.
FORMULA
a(n) = A000171(4*n+1).
MATHEMATICA
Needs["Combinatorica`"]; Table[ Print[an = GraphPolynomial[4*n + 1, x] /. x -> -1]; an, {n, 1, 9}] (* Jean-François Alcover, Aug 12 2013 *)
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
EXTENSIONS
Terms a(10) and beyond from Andrew Howroyd, Sep 17 2018
STATUS
approved