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A116108 Squares that are equal to the sum of 3 consecutive cubes. 12
0, 9, 36, 41616 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

m^3+(m+1)^3+(m+2)^3=3(1+m)*(3+2*m+m^2). Corresponding values of m are -1,0,1,23.

The equation s^2 = 3c^3 + 6c can be transformed using the substitution X = 3c, Y = 3s into Y^2 = X^3 + 18X, a form of the Weierstrass equation of an elliptic curve: Y^2 = X^3 + aX^2 + bX + c, with a = c = 0. We can now use the Sage program to show that there are no other integer solutions. - Jaap Spies, May 27 2007

Confirmed by MAGMA - see code below. - Warut Roonguthai, May 28 2007

That there are no other integer solutions is a theorem of Uchiyama, rediscovered by Cassels. For n consecutive cubes summing to a square, see A218979. - Jonathan Sondow, Apr 03 2014

LINKS

Table of n, a(n) for n=1..4.

J. W. S. Cassels, A Diophantine equation, Glasgow Math. J., 27 (1985), 11-18.

Saburo Uchiyama, On a Diophantine equation, Proc. Japan Acad., Ser. A 55 (1979), 367-369.

MATHEMATICA

Select[Total/@Partition[Range[-2, 200]^3, 3, 1], IntegerQ[Sqrt[#]]&] (* Harvey P. Dale, Aug 08 2015 *)

PROG

(MAGMA) IntegralPoints(EllipticCurve([18, 0]));

CROSSREFS

Cf. A027602, A218979.

Sequence in context: A203764 A053949 A071134 * A232257 A091961 A103758

Adjacent sequences:  A116105 A116106 A116107 * A116109 A116110 A116111

KEYWORD

fini,nonn,full

AUTHOR

Zak Seidov, Apr 14 2007

STATUS

approved

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Last modified November 22 16:31 EST 2019. Contains 329396 sequences. (Running on oeis4.)