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A216822
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Numbers n such that 2^n == 2 (mod n*(n+1)).
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7
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1, 5, 13, 29, 37, 61, 73, 157, 181, 193, 277, 313, 397, 421, 457, 541, 561, 613, 661, 673, 733, 757, 877, 997, 1093, 1153, 1201, 1213, 1237, 1289, 1321, 1381, 1453, 1621, 1657, 1753, 1873, 1905, 1933, 1993, 2017, 2137, 2341, 2473, 2557, 2593, 2797, 2857, 2917
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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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MATHEMATICA
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Select[Range[1, 10000], Mod[2^# - 2, # (# + 1)] == 0 &] (* T. D. Noe, Sep 19 2012 *)
Join[{1}, Select[Range[3000], PowerMod[2, #, #(#+1)]==2&]] (* Harvey P. Dale, Oct 05 2022 *)
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PROG
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(Python)
A216822_list = [n for n in range(1, 10**6) if n == 1 or pow(2, n, n*(n+1)) == 2] # Chai Wah Wu, Mar 25 2021
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CROSSREFS
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Cf. A069051 (prime n such that 2^n == 2 (mod n*(n-1))).
Cf. A217466 (prime terms of the sequence).
Cf. A217465 (composite terms of the sequence)
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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