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A216439 Smallest k such that k*n^3 + 1 is an n-th power. 3
1, 1, 37, 791, 95051, 111748, 2277696793, 484679258335, 229930796172439, 79792266297612, 66954547910007962117, 337165646545, 45082285083777592171142467, 2379140952844779936142872, 60722942736706550906445847537201, 78033832840595333890814363993704319 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
EXAMPLE
a(3) = 37 because 37*3^3 + 1 = 1000 = 10^3.
MAPLE
f:= proc(n) local S, x;
S:= subs(1=n^3+1, map(t -> rhs(op(t)), [msolve(x^n-1, n^3)]));
x:= min(S);
(x^n-1)/n^3
end proc:
f(1):= 1:
map(f, [$1..20]); # Robert Israel, Aug 26 2020
MATHEMATICA
a={}; Do[k = 2; While[ !IntegerQ[(k^n - 1)/n^3], k++ ]; AppendTo[a, (k^n-1)/n^3], {n, 1, 20}]; a
CROSSREFS
Sequence in context: A258463 A320551 A211834 * A333065 A251105 A144511
KEYWORD
nonn
AUTHOR
Michel Lagneau, Sep 10 2012
STATUS
approved

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Last modified July 14 02:38 EDT 2024. Contains 374291 sequences. (Running on oeis4.)