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Conjectured least number k such that prime(n) is the largest divisor of k^3 - 1, or 0 if there is no such k.
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%I #3 Apr 03 2013 22:52:09

%S 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,

%T 429,45,0,19,263,0,42,7600,32,12,58,1083163,520,0,48,880129,84,5320,

%U 92,14,39,13848,94,4195,718,15,21085,772,502068,5381,28,116,5579256

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

%C We allowed k to vary up to 10^7.

%t 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

%Y Cf. A223701-A223707 (related sequences).

%K nonn

%O 1,4

%A _T. D. Noe_, Apr 03 2013