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A118534
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a(n) = largest k such that prime(n+1) = prime(n) + (prime(n) mod k), or 0 if no such k exists.
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49
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0, 0, 3, 0, 9, 9, 15, 15, 17, 27, 25, 33, 39, 39, 41, 47, 57, 55, 63, 69, 67, 75, 77, 81, 93, 99, 99, 105, 105, 99, 123, 125, 135, 129, 147, 145, 151, 159, 161, 167, 177, 171, 189, 189, 195, 187, 199, 219, 225, 225, 227, 237, 231, 245, 251, 257, 267, 265, 273, 279
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| a(n) = prime(n) - g(n) or A000040(n) - A001223(n) if prime(n) - g(n) > g(n), 0 otherwise.
a(n) = 0 only for primes 2, 3 and 7.
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LINKS
| Remi Eismann, Table of n, a(n) for n = 1..10000
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EXAMPLE
| n=5: prime(5) = 11, prime(6) = 13, 13 = 11 + (11 mod 3) = 11 + (11 mod 9), so A117078(5) = 3, a(n) = 9 and A117563(5) = 9/3 = 3. Thus 11 has level 3 and so is a member of A117873.
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MATHEMATICA
| f[n_] := If[n == 1 || n == 2 || n == 4, 0, 2Prime[n] - Prime[n + 1]]; Array[f, 62] (* Robert G. Wilson v *)
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CROSSREFS
| Cf. A117078, A117563.
Cf. A117078, A117563, essentially the same as A117563.
Sequence in context: A181831 A080407 A197335 * A187427 A167352 A094472
Adjacent sequences: A118531 A118532 A118533 * A118535 A118536 A118537
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KEYWORD
| nonn,easy
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AUTHOR
| Remi Eismann (reismann(AT)free.fr), Apr 18 2006, Feb 14 2008
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EXTENSIONS
| Edited by N. J. A. Sloane (njas(AT)research.att.com), May 07 2006
More terms from Robert G. Wilson v (rgwv(at)rgwv.com), May 09 2006
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