|
Search: id:A056676
|
|
|
| A056676 |
|
Number of non-unitary but square-free divisors of C(n,[n/2]). Also number of non-square-free but unitary divisors of C(n,[n/2]). |
|
+0
1
|
|
| 0, 0, 0, 0, 0, 2, 0, 0, 4, 6, 0, 8, 8, 8, 8, 16, 0, 16, 0, 16, 32, 32, 0, 32, 48, 48, 56, 56, 96, 96, 64, 128, 128, 192, 256, 384, 384, 384, 512, 768, 512, 512, 512, 512, 448, 448, 768, 896, 896, 896, 896, 896, 768, 768, 2048, 2048, 4096, 4096, 2048, 2048, 2048, 2048
(list; graph; listen)
|
|
|
OFFSET
|
1,6
|
|
|
FORMULA
|
a(n)=A039593(n)-A000005[A055231(x)] =A039593(n)-A000005[A007913(x)/A055229(x)], where x=A001405(n)=C(n, [n/2])
|
|
EXAMPLE
|
n=14, C(14,7)=3432,has 32 divisors,16 unitary,16 square-free. The size of overlap is 8. The complementary parts are: non-unitary/square-free set={2,6,22,26,66,78,286,828}, while the unitary/not square-free set of equal size is: {8,24,88,104,264,312,1144,3432}.So a(14)=8.
|
|
CROSSREFS
|
A039593, A000005, A055231, A007913, A055229, A001405.
Sequence in context: A117434 A115179 A131742 this_sequence A098699 A021837 A153772
Adjacent sequences: A056673 A056674 A056675 this_sequence A056677 A056678 A056679
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Labos E. (labos(AT)ana.sote.hu), Aug 10 2000
|
|
|
Search completed in 0.002 seconds
|
