

A223707


Conjectured least number k such that prime(n) is the largest divisor of k^3 + 1, or 0 if there is no such k.


6



1, 2, 0, 3, 0, 4, 0, 8, 0, 0, 6, 11, 122, 7, 0, 582, 0, 14, 30, 212, 9, 24, 82, 88, 36, 1817, 47, 0, 46, 677, 20, 654, 136, 43, 2383, 33, 13, 59, 166, 1037, 210682, 49, 381, 85, 23245, 93, 15, 40, 18613, 95, 5591, 1433, 16, 0, 1798, 788, 26361, 29, 117, 842
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OFFSET

1,2


COMMENTS

We allowed k to vary up to 10^7.


LINKS

Table of n, a(n) for n=1..60.


MATHEMATICA

nn = 60; t = Table[0, {nn}]; ps = Prime[Range[nn]]; Do[num = n^3 + 1; j = 0; lastP = 0; While[num > 0 && j < nn, j++; p = ps[[j]]; While[Mod[num, p] == 0, lastP = j; num = num/p]]; If[num == 1 && t[[lastP]] == 0, t[[lastP]] = n; Print[{lastP, n}]], {n, 10^7}]; t


CROSSREFS

Cf. A223701A223706 (related sequences).
Sequence in context: A097852 A008801 A073739 * A046767 A115720 A053120
Adjacent sequences: A223704 A223705 A223706 * A223708 A223709 A223710


KEYWORD

nonn


AUTHOR

T. D. Noe, Apr 03 2013


STATUS

approved



