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A223706 Conjectured least number k such that prime(n) is the largest divisor of k^3 - 1, or 0 if there is no such k. 1
0, 0, 0, 2, 0, 3, 18, 7, 0, 30, 5, 10, 0, 6, 6205, 0, 178, 13, 29, 0, 8, 23, 0, 0, 35, 102, 46, 429, 45, 0, 19, 263, 0, 42, 7600, 32, 12, 58, 1083163, 520, 0, 48, 880129, 84, 5320, 92, 14, 39, 13848, 94, 4195, 718, 15, 21085, 772, 502068, 5381, 28, 116, 5579256 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

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. A223701-A223707 (related sequences).

Sequence in context: A105418 A280180 A135433 * A261162 A218862 A243199

Adjacent sequences:  A223703 A223704 A223705 * A223707 A223708 A223709

KEYWORD

nonn

AUTHOR

T. D. Noe, Apr 03 2013

STATUS

approved

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Last modified July 5 20:21 EDT 2020. Contains 335473 sequences. (Running on oeis4.)