

A227079


Solutions n to the Diophantine equation: n = (2*x^2  1)^2 = (6*y^2  5).


1




OFFSET

0,2


COMMENTS

x = {1, 2, 3, 6, 91} = A180445(n).
y = {1, 3, 7, 29, 6761} = A227077(n).
(sqrt(2*sqrt(n) + 2)  1)^2 is a RamanujanNagell Square = {1, 9, 25, 121, 32761} = A227078(n).


REFERENCES

J.M. De Koninck, Ces nombres qui nous fascinent, Entry 181, p. 56, Ellipses, Paris 2008.
L. J. Mordell, Diophantine Equations, Academic Press, NY, 1969, p. 205.


LINKS

Table of n, a(n) for n=0..4.
Richard K. Guy, The Strong Law of Small Numbers (example #29).
Eric Weisstein's World of Mathematics, Ramanujan's Square Equation


CROSSREFS

Cf. A060728, A180445, A227077, A227078.
Sequence in context: A089552 A017354 A239607 * A251222 A250967 A245033
Adjacent sequences: A227076 A227077 A227078 * A227080 A227081 A227082


KEYWORD

nonn,fini,full


AUTHOR

Raphie Frank, Aug 08 2013


STATUS

approved



