|
Search: id:A064765
|
|
|
| A064765 |
|
a(n) is the smallest number such that for, all m<n, both a(n)*a(m) and a(n)+a(m) are non-squares. |
|
+0
1
|
|
| 1, 2, 5, 6, 12, 17, 21, 22, 26, 29, 33, 39, 40, 46, 51, 53, 56, 57, 66, 73, 77, 85, 86, 89, 97, 101, 102, 106, 114, 117, 131, 133, 134, 135, 137, 141, 146, 149, 151, 161, 165, 166, 176, 177, 181, 182, 197, 201, 202, 206, 209, 211, 214, 221, 229, 231, 237, 241, 246
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
No number occurs more than once in the sequence because if a(n)=m then if m occurs again then a(n)*m=m^2. a(n) is always bigger then a(n-1) because all numbers less than a(n-1) have been checked to see if they make a square and if any do then because of the uniqueness of each value of a(n) then they must have already occurred in the sequence previously.
|
|
EXAMPLE
|
a(4) = 6 because a(1)*6 = 6, a(2)*6 = 12, a(3)*6 = 30 and a(1)+6 = 7, a(2)+6 = 8, a(3)+6=11, all non-squares
|
|
CROSSREFS
|
Sequence in context: A085206 A058601 A108365 this_sequence A082552 A057683 A069480
Adjacent sequences: A064762 A064763 A064764 this_sequence A064766 A064767 A064768
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Jonathan Ayres (jonathan.ayres(AT)btinternet.com), Oct 18 2001
|
|
|
Search completed in 0.002 seconds
|
