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Search: id:A060253
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| A060253 |
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Numbers n such that difference between n-th prime and n-th composite number is prime. |
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+0
3
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| 1, 2, 3, 4, 7, 9, 10, 11, 13, 14, 19, 24, 25, 32, 34, 37, 60, 64, 65, 67, 71, 75, 79, 83, 87, 95, 104, 105, 111, 115, 124, 130, 132, 133, 138, 145, 152, 153, 161, 163, 166, 174, 182, 187, 188, 190, 212, 213, 217, 220, 243, 246, 251, 255, 257, 264, 275, 279, 281
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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Values of n such that A000040(n)-A002808(n)=p(n)-c(n) is a prime number.
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EXAMPLE
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n=10: p(10)=29, c(10)=18, c(10)-p(10)=11, so 10=a(7) is here.
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MATHEMATICA
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f[ n_Integer ] := Block[ {k = n + PrimePi[ n ] + 1}, While[ k - PrimePi[ k ] - 1 != n, k++ ]; k ]; Select[ Range[ 500 ], PrimeQ[ Prime[ # ] - f[ # ] ] & ]
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CROSSREFS
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Numbers n such that A038529(n) is prime. Cf. A000040, A002808.
Sequence in context: A047548 A095378 A141489 this_sequence A066276 A139442 A047340
Adjacent sequences: A060250 A060251 A060252 this_sequence A060254 A060255 A060256
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KEYWORD
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easy,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 22 2001
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