OFFSET
1,3
COMMENTS
Same as number of Lyndon words of length n over Z_5 with trace 2 and subtrace 4; trace 3 and subtrace 4; trace 4 and subtrace 1. Same as number of Lyndon words of length n over GF(5) with trace 1 and subtrace 1; trace 2 and subtrace 4; trace 3 and subtrace 4; trace 4 and subtrace 1.
LINKS
Max Alekseyev, PARI/GP scripts for miscellaneous math problems
Frank Ruskey, 5-ary Lyndon words with given trace and subtrace
EXAMPLE
a(3;2,4)=2 since the two 5-ary Lyndon words of trace 2, subtrace 4 and length 3 are { 124, 142 }.
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