|
| |
|
|
A073706
|
|
a(n) = sum_{ d divides n } (n/d)^(3d).
|
|
0
| |
|
|
1, 9, 28, 129, 126, 1458, 344, 8705, 20413, 49394, 1332, 1104114, 2198, 2217546, 16305408, 33820673, 4914, 532253187, 6860, 2392632274, 10500716072, 8591716802, 12168, 422182489826, 30517593751, 549760658274, 7625984925160
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
FORMULA
| G.f.: Sum_{n=1..inf} -ln(1 - (n^3)*x^n)/n = Sum_{n=1..inf} a(n) x^n/n.
G.f.: sum(k>=1, k^3*x^k/(1-k^3*x^k)). - Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 21 2003
|
|
|
EXAMPLE
| a(10) = (10/1)^(3*1) +(10/2)^(3*2) +(10/5)^(3*5) +(10/10)^(3*10) = 49394 because positive divisors of 10 are 1, 2, 5, 10.
|
|
|
CROSSREFS
| Cf. A055225, A073705.
Sequence in context: A085292 A198059 A181090 * A042501 A041154 A024121
Adjacent sequences: A073703 A073704 A073705 * A073707 A073708 A073709
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Paul D. Hanna (pauldhanna(AT)juno.com), Aug 04 2002
|
| |
|
|
