A062061 Numbers k such that prime(k)+1 divides k^2.
2, 4, 70, 516, 174080, 292050, 637320, 687105342, 14342420320, 214517880600
Offset: 1
Keywords
Examples
Prime(4)+1 = 7+1 divides 4^2, so 4 is a term of the sequence.
Programs
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Mathematica
Select[Range[10^6], Mod[ #^2, Prime[ # ] + 1] == 0 &] Select[Range[640000],PowerMod[#,2,Prime[#]+1]==0&] (* The program generates the first seven terms of the sequence. To generate more, increase the Range constant. *) (* Harvey P. Dale, Apr 23 2022 *)
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PARI
isok(n) = n^2 % (prime(n)+1) == 0; \\ Michel Marcus, Apr 15 2017
Extensions
a(8) from Donovan Johnson, Oct 14 2009
a(9)-a(10) from Giovanni Resta, Apr 15 2017
Comments