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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 (list; graph; refs; listen; history; text; internal format)
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(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.

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

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Last modified November 15 06:11 EST 2019. Contains 329144 sequences. (Running on oeis4.)