|
|
A054614
|
|
a(n) = Sum_{d|n} phi(d)*7^(n/d).
|
|
3
|
|
|
0, 7, 56, 357, 2464, 16835, 118104, 823585, 5767328, 40354335, 282492280, 1977326813, 13841410464, 96889010491, 678223896728, 4747561544985, 33232936339456, 232630513987319, 1628413638500376, 11398895185373269
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
|
|
PROG
|
(PARI) a(n) = sumdiv(n, d, eulerphi(d)*7^(n/d)); \\ Michel Marcus, Jul 11 2021
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|