

A030064


1 + product of any two terms is a square.


0




OFFSET

1,2


REFERENCES

Martin Gardner, probably "Mathematical Magic Show".


LINKS

Table of n, a(n) for n=1..5.
A. Baker and H. Davenport, The Equations 3x^22=y^2 and 8x^27=z^2, Quart. J. Math. Oxford 20 (1969).


EXAMPLE

0*2,4,12,420 + 1 = 1
2*4 + 1 = 9
2*12 + 1 = 25
2*420 + 1 = 841 > sqrt = 29
4*12 + 1 = 49
4*420 + 1 = 1681 > sqrt = 41
12*420 + 1 = 5041 > sqrt = 71


CROSSREFS

Sequence in context: A291827 A287059 A059085 * A224886 A180500 A176990
Adjacent sequences: A030061 A030062 A030063 * A030065 A030066 A030067


KEYWORD

nonn,fini,full


AUTHOR

Timothy Chow (tchow(AT)math.lsa.umich.edu)


EXTENSIONS

Corrected by Mitch Harris, Apr 24 2006


STATUS

approved



