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A247165
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Numbers m such that m^2 + 1 divides 2^m - 1.
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4
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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0 is in this sequence because 0^2 + 1 = 1 divides 2^0 - 1 = 1.
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MAPLE
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select(n -> (2 &^ n - 1) mod (n^2 + 1) = 0, [$1..10^6]); # Robert Israel, Dec 02 2014
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MATHEMATICA
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a247165[n_Integer] := Select[Range[0, n], Divisible[2^# - 1, #^2 + 1] &]; a247165[1500000] (* Michael De Vlieger, Nov 30 2014 *)
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PROG
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(Magma) [n: n in [1..100000] | Denominator((2^n-1)/(n^2+1)) eq 1];
(PARI) for(n=0, 10^9, if(Mod(2, n^2+1)^n==+1, print1(n, ", "))); \\ Joerg Arndt, Nov 30 2014
(Python)
A247165_list = [n for n in range(10**6) if n == 0 or pow(2, n, n*n+1) == 1]
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CROSSREFS
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Cf. A247219 (n^2 - 1 divides 2^n - 1), A247220 (n^2 + 1 divides 2^n + 1).
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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