|
Search: id:A050521
|
|
|
| A050521 |
|
Number of factorizations of (n,2*n) into pairs (k,l). |
|
+0
1
|
|
| 1, 1, 1, 3, 1, 7, 1, 10, 4, 7, 1, 33, 1, 7, 9, 28, 1, 39, 1, 33
(list; graph; listen)
|
|
|
OFFSET
|
1,4
|
|
|
COMMENT
|
Pairs (k,l) must satisfy 0<k, 0<l; if k=1 then l=1. Definition of "*": (a,b)*(x,y)=(a*x,b*y); unit is (1,1).
|
|
EXAMPLE
|
(10,20) = (2,1)*(5,20) = (2,20)*(5*1) = (2,2)*(5,10) = (2,10)*(5,2) = (2,4)*(5,5) = (2,5)*(5,4); so a(10) = 7.
|
|
CROSSREFS
|
Cf. A051707.
Sequence in context: A099749 A077202 A086665 this_sequence A098093 A114712 A089741
Adjacent sequences: A050518 A050519 A050520 this_sequence A050522 A050523 A050524
|
|
KEYWORD
|
nonn,nice,easy,more
|
|
AUTHOR
|
Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp)
|
|
|
Search completed in 0.004 seconds
|
