A047698 Numbers that are the sum of four positive seventh powers in two or more ways.

2056364173794800, 12191487610289536, 263214614245734400, 696885239160606459, 1560510414117060608, 4497268448089227600, 18896044524917750533, 25704745581139341318, 26662783403703215232, 33691470623454003200, 44053472466326057527, 100502405478837434259

Offset

1,1

Links

Table of n, a(n) for n=1..12.

D. J. Bernstein, Enumerating solutions to p(a) + q(b) = r(c) + s(d)

R. L. Ekl, New Results in Equal Sums of Like Powers, Math. Comput. 67, 1309-1315, 1998.

Example

4497268448089227600 = 30^7 + 42^7 + 369^7 + 447^7 = 45^7 + 270^7 + 387^7 + 438^7. - Sean A. Irvine, May 15 2021

Crossrefs

Cf. A025367, A025406, A309763.

Sequence in context: A335044 A216910 A309111 * A246252 A058445 A290540

Adjacent sequences: A047695 A047696 A047697 * A047699 A047700 A047701

Keyword

nonn,hard

Author

N. J. A. Sloane

Extensions

Corrected by D. J. Bernstein (djb(AT)cr.yp.to)

a(6)-a(12) from Sean A. Irvine, May 14 2021

Status

approved