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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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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, (n-a^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 A342618 A258806
KEYWORD
nonn,easy
AUTHOR
STATUS
approved

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Last modified June 25 18:39 EDT 2024. Contains 373707 sequences. (Running on oeis4.)