|
|
A054664
|
|
Number of 4-ary Lyndon words of length n with trace 0 mod 4.
|
|
1
|
|
|
1, 1, 5, 14, 51, 165, 585, 2032, 7280, 26163, 95325, 349350, 1290555, 4792905, 17895679, 67106816, 252645135, 954429840, 3616814565, 13743869130, 52357696365, 199911109725, 764877654105, 2932030657200, 11258999068416
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,3
|
|
COMMENTS
|
Also number of 4-ary Lyndon words of length n with trace 2 mod 4.
|
|
LINKS
|
|
|
FORMULA
|
|
|
MATHEMATICA
|
a[n_] := 1/(4 n) Sum[GCD[d, 4] MoebiusMu[d] 4^(n/d), {d, Divisors[n]}];
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|