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Search: id:A125855
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| A125855 |
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Numbers n such that n+1, n+3, n+7 and n+9 are all primes. |
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+0
2
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| 4, 10, 100, 190, 820, 1480, 1870, 2080, 3250, 3460, 5650, 9430, 13000, 15640, 15730, 16060, 18040, 18910, 19420, 21010, 22270, 25300, 31720, 34840, 43780, 51340, 55330, 62980, 67210, 69490, 72220, 77260, 79690, 81040, 82720, 88810, 97840
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It seems that, with the exception of 4, all terms are multiples of 10. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 24 2006
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MAPLE
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a:=proc(n): if isprime(n+1)=true and isprime(n+3)=true and isprime(n+7)=true and isprime(n+9)=true then n else fi end: seq(a(n), n=1..500000); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 24 2006
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MATHEMATICA
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Do[If[(PrimeQ[x + 1]) && (PrimeQ[x + 3]) && (PrimeQ[x + 7]) && (PrimeQ[x + 9]), Print[x]], {x, 1, 10000}]
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CROSSREFS
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Cf. A057015, A125779, A125780.
Sequence in context: A059919 A143047 A156329 this_sequence A153743 A098449 A118378
Adjacent sequences: A125852 A125853 A125854 this_sequence A125856 A125857 A125858
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KEYWORD
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nonn
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AUTHOR
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Artur Jasinski (grafix(AT)csl.pl), Dec 12 2006
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 24 2006
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