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A093546
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Numbers n such that n divides 2^n^2 + 1.
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5
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1, 3, 9, 27, 57, 81, 171, 243, 513, 729, 1083, 1467, 1539, 2187, 3249, 4401, 4617, 6561, 9747, 13203, 13851, 19683, 20577, 27873, 29241, 32547, 39393, 39609, 41553, 59049, 61731, 83619, 87723, 97641, 118179, 118827, 124659, 177147, 185193, 239121
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| This sequence is closed under multiplication. A006521 is a subsequence of this sequence. A006521 is also closed under multiplication. In fact if m is even and k is a natural number then the sequence " n divides m^n^k + 1 " is a subsequence of the sequence " n divides m^n^(k+1)+ 1 " and both are closed under multiplication.
"Closed under multiplication" means that if x and y are terms then so it x*y.
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MATHEMATICA
| Select[ Range[250857], PowerMod[2, #^2, # ] == # - 1 &] (from Robert G. Wilson v Apr 02 2004)
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CROSSREFS
| Cf. A006521, A067945, A093547.
Sequence in context: A181047 A014948 A093665 * A015955 A097803 A201202
Adjacent sequences: A093543 A093544 A093545 * A093547 A093548 A093549
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KEYWORD
| nonn
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AUTHOR
| Farideh Firoozbakht (mymontain(AT)yahoo.com), Mar 31 2004
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EXTENSIONS
| Corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 02 2004
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