|
|
A054612
|
|
a(n) = Sum_{d|n} phi(d)*5^(n/d).
|
|
5
|
|
|
0, 5, 30, 135, 660, 3145, 15810, 78155, 391320, 1953405, 9768870, 48828175, 244157820, 1220703185, 6103593930, 30517584915, 152588282640, 762939453205, 3814699250430, 19073486328215, 95367441415140, 476837158360185, 2384185839844050
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
|
|
PROG
|
(PARI) a(n) = if (n, sumdiv(n, d, eulerphi(d)*5^(n/d)), 0); \\ Michel Marcus, Apr 16 2021
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|