

A067632


n(n+180) is a square.


1



2116, 768, 500, 324, 240, 196, 192, 180, 0, 12, 16, 60, 144, 320, 588, 1936
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OFFSET

0,1


COMMENTS

Rewrite it as s^2  t^2 = 90^2 to see that there are only finitely many solutions.


REFERENCES

Albert H. Beiler, Recreations in the Theory of Numbers (2d ed. 1966), pp. 296, 317.


LINKS

Table of n, a(n) for n=0..15.


EXAMPLE

588 is included because 588 * (588 + 180) = 451584, the square root of which is 672.


MAPLE

isolve(n*(n+180)=m^2);


MATHEMATICA

Select[Range[2200, 2200], IntegerQ[Sqrt[#(#+180)]]&] (* Harvey P. Dale, Jun 11 2019 *)


CROSSREFS

Sequence in context: A107528 A246808 A217439 * A236446 A077731 A077733
Adjacent sequences: A067629 A067630 A067631 * A067633 A067634 A067635


KEYWORD

sign,fini,full


AUTHOR

Harvey P. Dale, Feb 02 2002


STATUS

approved



