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A134930
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Nearest-neighbors of twin primes.
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5
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2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 28, 30, 32, 40, 42, 44, 58, 60, 62, 70, 72, 74, 100, 102, 104, 106, 108, 110, 136, 138, 140, 148, 150, 152, 178, 180, 182, 190, 192, 194, 196, 198, 200, 226, 228, 230, 238, 240, 242, 268, 270, 272, 280, 282, 284
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OFFSET
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1,1
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COMMENTS
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This sequence consists of the number 2 followed by the triplet composites: A134928.
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LINKS
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Table of n, a(n) for n=1..55.
O. E. Pol, Determinacion geometrica de los numeros primos y compuesto.
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FORMULA
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a(1)=2. For n>2, a(n)=A134928(n-1)
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EXAMPLE
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2, 4 and 6 are nearest-neighbors of twin primes because 3 and 5 are twin primes.
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MATHEMATICA
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f[{a_, b_}]:={a-1, a+1, b+1}; Union[Flatten[f/@Select[Partition[Prime[ Range[ 100]], 2, 1], Last[#]-First[#]==2&]]] (* From Harvey P. Dale, Aug 16 2011 *)
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CROSSREFS
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Sequence in context: A221284 A085125 A194402 * A084562 A187350 A118070
Adjacent sequences: A134927 A134928 A134929 * A134931 A134932 A134933
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KEYWORD
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easy,nonn
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AUTHOR
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Omar E. Pol, Nov 16 2007
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STATUS
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approved
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