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A266985 Least positive integer x such that n + x^3 = y^2 + z^5 for some positive integers y and z, or 0 if no such x exists. 2
7, 1, 2, 34, 1, 55, 3, 5, 30, 1, 3, 242, 6, 7, 3, 26, 1, 4, 2, 7, 5, 3, 62, 3, 77, 1, 107, 10, 2, 2, 3, 6, 1, 2, 128, 1, 1, 4, 3, 11, 1, 3, 2, 6, 7, 5, 22, 1, 50, 1, 7, 5, 6, 16, 3, 3, 1, 2, 4, 62, 2, 17, 19, 6, 1, 8, 14, 1, 4, 3, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
The general conjecture in A266277 implies that for any integer m there are positive integers x, y and z with m + x^3 = y^2 + z^5.
See also A266277 and A266528 for similar conjectures.
LINKS
EXAMPLE
a(0) = 7 since 0 + 7^3 = 10^2 + 3^5.
a(3) = 34 since 3 + 34^3 = 150^2 + 7^5.
a(8) = 30 since 8 + 30^3 = 101^2 + 7^5.
a(11) = 242 since 11 + 242^3 = 3420^2 + 19^5.
a(766) = 90891 since 766 + 90891^3 = 11850281^2 + 906^5.
MATHEMATICA
SQ[n_]:=SQ[n]=IntegerQ[Sqrt[n]]
Do[x=1; Label[bb]; Do[If[SQ[n+x^3-y^5], Print[n, " ", x]; Goto[aa]], {y, 1, (n+x^3-1)^(1/5)}]; x=x+1; Goto[bb]; Label[aa]; Continue, {n, 0, 70}]
CROSSREFS
Sequence in context: A316953 A317733 A258335 * A286912 A239807 A130875
KEYWORD
nonn
AUTHOR
Zhi-Wei Sun, Jan 08 2016
STATUS
approved

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Last modified February 25 04:28 EST 2024. Contains 370309 sequences. (Running on oeis4.)