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Search: id:A111441
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| A111441 |
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Numbers n such that the sum of the squares of the first n primes is divisible by n. |
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+0
23
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| 1, 19, 37, 455, 509, 575, 20597, 202717, 1864637, 542474231, 1139733677
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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The sum of the squares of the first 19 primes 2^2 + 3^2 + 5^2 + ... + 67^2 = 19*1314, thus 19 is in an element of the sequence.
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MATHEMATICA
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s = 0; t = {}; Do[s = s + Prime[n]^2; If[ Mod[s, n] == 0, AppendTo[t, n]], {n, 10^8}]; t (* Robert G. Wilson v *)
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PROGRAM
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(MuPAD): a := 0; for n from 1 to 100000 do a := a + ithprime(n)^2; if a/n = trunc(a/n) then print(n); end_if; end_for;
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CROSSREFS
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Cf. A045345.
Sequence in context: A050528 A053685 A136063 this_sequence A144594 A123028 A067205
Adjacent sequences: A111438 A111439 A111440 this_sequence A111442 A111443 A111444
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KEYWORD
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nonn
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AUTHOR
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Stefan Steinerberger (hansibal(AT)hotmail.com), Nov 14 2005
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EXTENSIONS
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a(8)&a(9) from Robert G. Wilson v (rgwv(at)rgwv.com), Nov 15 2005
2 more terms from Ryan Propper (rpropper(AT)stanford.edu), Mar 27 2007
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