OFFSET
1,3
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..100
M. Domaratzki, Improved bounds on the number of automata accepting finite languages, in Computing and Combinatorics Conference: COCOON'02.
M. Domaratzki, Improved bounds on the number of automata accepting finite languages, Internat. J. Found. Comput. Sci. 15 (2004), 143-161.
FORMULA
a(n) = 2*(2n-3)*a(n-1) + 2*(2n-5)*(n-4)*a(n-2) for n >= 4; a(n) = A000407(n-2) for n <= 3.
PROG
(PARI) { for (n=1, 100, if (n>3, a=2*(2*n-3)*a1 + 2*(2*n-5)*(n-4)*a2; a2=a1; a1=a, if (n>2, a=a1=6, a=a2=1)); write("b064815.txt", n, " ", a) ) } \\ Harry J. Smith, Sep 27 2009
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Mike Domaratzki (mdomaratzki(AT)alumni.uwaterloo.ca), Oct 22 2001
EXTENSIONS
a(16)-a(17) from Harry J. Smith, Sep 27 2009
STATUS
approved