|
Search: id:A073705
|
|
|
| A073705 |
|
a(n) = sum_{ d divides n } (n/d)^(2d). |
|
+0
2
|
|
| 1, 5, 10, 33, 26, 182, 50, 577, 811, 1750, 122, 16194, 170, 9491, 74900, 290, 847127, 362, 2498178, 4901060, 4209430, 530, 78564226, 9766251, 67138102, 387952660, 542674914, 842, 4866184552, 962, 8606778369, 31382832260, 17179953862
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
FORMULA
|
G.f.: Sum_{n=1..inf} -ln(1 - (n^2)*x^n)/n = Sum_{n=1..inf} a(n) x^n/n.
G.f.: sum(k>=1, k^2*x^k/(1-k^2*x^k)). - Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 21 2003
|
|
EXAMPLE
|
a(10) = (10/1)^(2*1) +(10/2)^(2*2) +(10/5)^(2*5) +(10/10)^(2*10) = 1750 because positive divisors of 10 are 1, 2, 5, 10.
|
|
CROSSREFS
|
Cf. A055225.
Sequence in context: A005201 A094234 A052538 this_sequence A121158 A032772 A117865
Adjacent sequences: A073702 A073703 A073704 this_sequence A073706 A073707 A073708
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Paul D. Hanna (pauldhanna(AT)juno.com), Aug 04 2002
|
|
|
Search completed in 0.002 seconds
|
