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A272897
Largest prime factor of n-th taxi-cab number A001235(n).
1
19, 19, 19, 43, 19, 13, 43, 19, 37, 79, 19, 19, 79, 79, 43, 61, 79, 127, 19, 19, 13, 43, 109, 19, 37, 139, 43, 19, 37, 31, 79, 43, 19, 139, 127, 127, 13, 19, 19, 61, 103, 151, 409, 73, 181, 13, 277, 79, 43, 79, 79, 19, 43, 139, 61, 19, 61, 79, 103, 127, 19, 37, 79, 163, 79, 19, 19
OFFSET
1,1
COMMENTS
There are two versions of "taxicab numbers" that are A001235 and A011541. This sequence focuses on the version A001235.
All terms of this sequence are members of this sequence infinitely many times. For example, in this sequence there are infinitely many times "277" and there are infinitely many times "17".
Is a(n) >= 13 for all n? This is true for n <= 10000. - Robert Israel, May 09 2016
LINKS
FORMULA
a(n) = A006530(A001235(n)).
EXAMPLE
a(1) = A006530(A001235(1)) = A006530(1729) = 19.
MATHEMATICA
FactorInteger[Select[Range[2*10^5], Length[PowersRepresentations[#, 2, 3]] > 1 &]][[All, -1, 1]] (* Michael De Vlieger, May 10 2016, after Harvey P. Dale at A001235 *)
CROSSREFS
Sequence in context: A010858 A291499 A168525 * A040343 A022353 A323177
KEYWORD
nonn
AUTHOR
Altug Alkan, May 09 2016
STATUS
approved