

A064765


a(n) is the smallest number such that for, all m<n, both a(n)*a(m) and a(n)+a(m) are nonsquares.


0



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
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OFFSET

1,2


COMMENTS

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 than a(n1) because all numbers less than a(n1) 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.


LINKS

Table of n, a(n) for n=1..59.


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 nonsquares


CROSSREFS

Sequence in context: A238481 A058601 A108365 * A257805 A082552 A243798
Adjacent sequences: A064762 A064763 A064764 * A064766 A064767 A064768


KEYWORD

nonn


AUTHOR

Jonathan Ayres (jonathan.ayres(AT)btinternet.com), Oct 18 2001


STATUS

approved



