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A138267
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Balanced prime numbers n such that n*(n+1)+1 is a balanced prime.
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0
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173, 68099, 76487, 96377, 336593, 488909, 1388381, 2625929, 2757767, 3189287, 3296021, 4057847, 4817399, 5223293, 5803769, 6495509, 6538997, 6569993, 6574769, 6914717, 8928389, 9021323, 9722789, 11439053, 11589467, 12471317, 15061973
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..27.
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MATHEMATICA
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NextPrime[n_Int]:=Module[{k}, k=n+1; While[ !PrimeQ[k], k++ ]; k]; PrevPrime[n_Int]:=Module[{k}, k=n-1; While[ !PrimeQ[k], k-- ]; k]; s=""; For[i=2, i< 10^5*2, p=Prime[i]; If[(Prime[i-1]+Prime[i+1])/2==p, r=p*(p+1)+1; a=PrevPrime[r]; b=NextPrime[r]; If[PrimeQ[r]&&r==(a+b)/2, (*Print[p, ":", a, ", ", b, "; ", r]*)s=s<>ToString[p]<>", "]]; i++ ]; Print[s]
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CROSSREFS
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Cf. A006562.
Sequence in context: A209809 A185707 A185701 * A096709 A180417 A160660
Adjacent sequences: A138264 A138265 A138266 * A138268 A138269 A138270
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KEYWORD
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nonn
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AUTHOR
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Vladimir Joseph Stephan Orlovsky, May 05 2008
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EXTENSIONS
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a(9)-a(27) from Donovan Johnson, Mar 26 2011
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STATUS
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approved
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