cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A291829 Numbers k such that k^3 is the sum of two positive 7th powers.

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%I A291829 #7 Apr 05 2021 20:43:01
%S A291829 32,4096,69984,524288,2500000,8957952,26353376,67108864,153055008,
%T A291829 320000000,623589472,1146617856,2007952544,3373232128,5467500000,
%U A291829 8589934592,13130837536,19591041024,28603895648,35723051649,40960000000,57634833312,79819452416,108954414304
%N A291829 Numbers k such that k^3 is the sum of two positive 7th powers.
%C A291829 When a^7 + b^7 = m, (m^2*a)^7 + (m^2*b)^7 = m^15 is a cube.
%C A291829 When k in this sequence, k*(n^7) (n = 2, 3, ... ) is also in this sequence.
%e A291829 32^3 = 4^7 + 4^7, so 32 is in the sequence.
%e A291829 35723051649^3 = 16641^7 + 33282^7, so 35723051649 is in the sequence.
%t A291829 lst={};Do[If[IntegerQ[(n^3-a^7)^(1/7)],AppendTo[lst,n]],{n,1.467*10^11},{a,(n^3/2)^(1/7)}]; lst
%Y A291829 Cf. A000578, A001015, A000404, A009003, A050801.
%K A291829 nonn
%O A291829 1,1
%A A291829 _XU Pingya_, Sep 03 2017