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Search: id:A137169
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| A137169 |
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a(0) = 2; for n>0, a(n) = smallest number m > a(n-1) such that both m-n and m+n are primes. |
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2
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| 2, 4, 5, 8, 9, 12, 13, 24, 39, 50, 51, 72, 85, 96, 117, 122, 123, 156, 175, 192, 213, 218, 219, 234, 247, 252, 255, 256, 279, 360, 367, 378, 399, 400, 423, 432, 455, 486, 525, 530, 531, 612, 619, 630, 657, 664, 687, 774, 775, 810, 837, 860, 915, 930, 937, 942
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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A variant of A087711. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 09 2008
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EXAMPLE
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4-1=3 prime, 4+1=5 prime; 5-2=3, 5+2=7; 8-3=5,8+3=11; 9-4=5,9+4=13;
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MAPLE
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A137169 := proc(n) option remember ; if n = 0 then RETURN(2) ; fi ; for a from A137169(n-1)+1 do if isprime(a-n) and isprime(a+n) then RETURN(a) ; fi ; od: end: seq(A137169(n), n=0..80) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 09 2008
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MATHEMATICA
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s = ""; k = 0; For[i = 3, i < 22^2, If[PrimeQ[i - k] && PrimeQ[i + k], s = s <> ToString[i] <> ", "; k++ ]; i++ ]; Print[s]
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CROSSREFS
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See A087711 for another version.
Adjacent sequences: A137166 A137167 A137168 this_sequence A137170 A137171 A137172
Sequence in context: A032787 A067366 A099628 this_sequence A002541 A102821 A101881
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KEYWORD
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nonn
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AUTHOR
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Vladimir Orlovsky (4vladimir(AT)gmail.com), Apr 03 2008
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 09 2008
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