|
|
A168649
|
|
a(n) = (1/n)*Sum_{d|n} moebius(d)*2^(n^2/d).
|
|
0
|
|
|
2, 6, 168, 16320, 6710880, 11453201760, 80421421917312, 2305843008676823040, 268650182136584246132736, 126765060022822827559679531520, 241677817415439249618874010960062464, 1858395433210885261794249658823668075069440
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
a(n) = (1/n)*Sum_{d|n} moebius(n/d)*(2^n)^d.
|
|
MATHEMATICA
|
a[n_] := DivisorSum[n, MoebiusMu[#] * 2^(n^2/#) &] / n; Array[a, 10] (* Amiram Eldar, Aug 18 2023 *)
|
|
PROG
|
(PARI) a(n)=(1/n)*sumdiv(n, d, moebius(d)*2^(n^2/d))
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|