

A003369


Numbers that are the sum of 2 positive 7th powers.


41



2, 129, 256, 2188, 2315, 4374, 16385, 16512, 18571, 32768, 78126, 78253, 80312, 94509, 156250, 279937, 280064, 282123, 296320, 358061, 559872, 823544, 823671, 825730, 839927, 901668, 1103479, 1647086, 2097153, 2097280, 2099339, 2113536
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OFFSET

1,1


LINKS

Robert Israel, Table of n, a(n) for n = 1..10000


EXAMPLE

From David A. Corneth, Aug 03 2020: (Start)
3909794986386 is in the sequence as 3909794986386 = 57^7 + 57^7.
6061605477062 is in the sequence as 6061605477062 = 19^7 + 67^7.
26019535290982 is in the sequence as 26019535290982 = 61^7 + 81^7. (End)


MAPLE

N:= 10^7: # to get all terms <= N
S:= select(`<=`, {seq(seq(a^7+b^7, a=1..b), b=1..floor(N^(1/7)))}, N):
sort(convert(S, list)); # Robert Israel, Sep 03 2017


MATHEMATICA

lst={}; Do[If[(a^7+b^7)==n, AppendTo[lst, n]], {n, 200000}, {a, (n/2)^(1/7)}, {b, a, (na^7)^(1/7)}]; lst (* XU Pingya, Sep 03 2017 *)
Module[{upto=10}, Select[Union[Total/@Tuples[Range[upto]^7, 2]], #<= (upto^7)&]] (* Harvey P. Dale, Feb 04 2019 *)


CROSSREFS

Cf. A000404 (2 squares), A003325 (2 cubes), A003336 (2 4th), A003347 (2 5th), A003358 (2 6th), A088719 (2 distinct 7th), A003380 (2 8th).
Cf. A001015 (seventh powers).
Sequence in context: A153425 A296060 A090121 * A303377 A258806 A216358
Adjacent sequences: A003366 A003367 A003368 * A003370 A003371 A003372


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane


STATUS

approved



