A249751 Numbers m such that m - 2 divides m^m + 2.
3, 4, 7, 8, 67, 260, 379, 1191, 1471, 5076, 25807, 58591, 103780, 134947, 137347, 170587, 203236, 272611, 285391, 420211, 453748, 538735, 540856, 592411, 618451, 680707, 778807, 1163067, 1306936, 1520443, 1700947, 1891336, 2099203, 2831011, 3481960, 4020031
Offset: 1
Keywords
Examples
3 is in this sequence because (3^3 + 2)/(3 - 2) = 29 is an integer.
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..160
Programs
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Magma
[n: n in [3..10000] | Denominator((n^n+2)/(n-2)) eq 1];
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Mathematica
fQ[n_] := Mod[ PowerMod[ n, n, n - 2] + 2, n - 2] == 0; Select[ Range@ 4100000, fQ] (* Robert G. Wilson v, Dec 19 2014 *)
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Python
A249751_list = [n for n in range(3,10**7) if n==3 or pow(n,n,n-2) == n-4] # Chai Wah Wu, Dec 06 2014
Extensions
More terms from Chai Wah Wu, Dec 06 2014