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A121234 Natural integers x such that x*(x+1)*(x+2)+1 is a square. +0
1
0, 2, 4, 55 (list; graph; listen)
OFFSET

1,2

COMMENT

The sequence is finite by Thue's theorem

n(n + 1)(n + 2) + 1 = n^3 + 3*n^2 + 2*n + 1. The set of x values of integral solutions to the elliptic curve y^2 = n^3 + 3*n^2 + 2*n + 1 (see MAGMA program) is { -2, -1, 0, 2, 4, 55 }. So the sequence is complete. - Mohamed Bouhamida (bhmd95(AT)yahoo.fr), Nov 29 2007

MAPLE

(MAGMA) P<n> := PolynomialRing(Integers()); {x: x in Sort([ p[1] : p in IntegralPoints(EllipticCurve(n^3 + 3*n^2 + 2*n + 1)) ])}; - Mohamed Bouhamida (bhmd95(AT)yahoo.fr), Nov 29 2007

CROSSREFS

Sequence in context: A018337 A092389 A005274 this_sequence A084574 A087621 A062784

Adjacent sequences: A121231 A121232 A121233 this_sequence A121235 A121236 A121237

KEYWORD

fini,nonn,full

AUTHOR

Roger Cuculiere (rcuculiere(AT)free.fr), Aug 21 2006

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Last modified September 6 09:40 EDT 2008. Contains 143480 sequences.


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