|
|
A345274
|
|
a(n) = Sum_{d|n} (n-d)^tau(n/d).
|
|
0
|
|
|
0, 1, 4, 31, 16, 650, 36, 2633, 548, 6650, 100, 1782390, 144, 28754, 38660, 799583, 256, 24192515, 324, 47154588, 160520, 195002, 484, 78424725898, 14224, 391370, 471124, 387887498, 784, 500247950884, 900, 912432417, 1049960, 1187234, 1338020, 78818475807611, 1296, 1875818
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,3
|
|
COMMENTS
|
If p is prime, a(p) = Sum_{d|p} (p-d)^tau(p/d) = (p-1)^2 + 0^1 = (p-1)^2.
|
|
LINKS
|
|
|
EXAMPLE
|
a(10) = Sum_{d|10} (10-d)^tau(10/d) = 9^4 + 8^2 + 5^2 + 0^1 = 6650.
|
|
MATHEMATICA
|
Table[Sum[(n - k)^DivisorSigma[0, n/k] (1 - Ceiling[n/k] + Floor[n/k]), {k, n}], {n, 50}]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|