|
Search: id:A114863
|
|
| |
|
| 1, 0, 1, 1, 1, 2, 3, 3, 4, 7, 7, 10, 18, 18, 26, 45, 44, 64, 113, 112, 163, 287, 285, 416, 733, 731, 1067, 1885, 1885
(list; graph; listen)
|
|
|
OFFSET
|
1,6
|
|
|
COMMENT
|
This sequence is an approximation of a triple factorial analogue to Stirling's approximation to factorial. Note that a(n) is exact for n = 1, 3, 6.
|
|
FORMULA
|
a(n) = Floor[n^(n/3)/n!!! ]. a(n) = Floor[CubeRoot(A000312(n))/A007661(n)].
|
|
EXAMPLE
|
a(9) = Floor[(9^3)/162] = Floor[4.5] = 4.
a(10) = Floor[(10^3.33333)/280] = Floor[7.69381906] = 7.
a(27) = Floor[(27^9)/7142567040] = Floor[1067.62701] = 1067.
|
|
CROSSREFS
|
Cf. A000312, A006882, A055775, A007661.
Sequence in context: A119795 A119614 A035540 this_sequence A152980 A035535 A154309
Adjacent sequences: A114860 A114861 A114862 this_sequence A114864 A114865 A114866
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Jonathan Vos Post (jvospost3(AT)gmail.com), Feb 20 2006
|
|
|
Search completed in 0.002 seconds
|
