OFFSET
1,4
COMMENTS
Same as the number of 4-ary Lyndon words of length n over Z_4 with trace 3 and subtrace 3.
LINKS
EXAMPLE
a(4;3,3)=4 since the four 4-ary Lyndon words of trace 3, subtrace 3 and length 4 are { 0111, 0133, 0313, 0331 }.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Frank Ruskey and Nate Kube, Aug 22 2002
EXTENSIONS
Terms a(16) onward from Max Alekseyev, Apr 09 2013
STATUS
approved