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Search: id:A055738
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| A055738 |
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Number of prime quadruples < 10^n, where a prime quadruple means 4 successive primes {p, p', p'', p'''} with p''' = p + 8. |
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+0
2
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OFFSET
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1,2
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REFERENCES
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J. Recreational Math., vol. 23, No. 2, 1991, p. 97.
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LINKS
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Index entries for sequences related to numbers of primes in various ranges
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EXAMPLE
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For n=2 the quadruples are 3,5,7,11; 5,7,11,13; 11,13,17,19.
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MAPLE
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with(numtheory): x := 1229; t1 := [seq(ithprime(i), i=1..x)]; c := 0: for i from 1 to x-3 do if t1[i]+8 = t1[i+3] then c := c+1; fi; od: c; # the values of x to use are given by A006880.
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MATHEMATICA
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x=168; a=Table[ Prime[ n ], {n, 1, x} ]; c=0; Do[ If[ a[ [ n ] ]+8==a[ [ n+2 ] ], c++ ], {n, 1, x-3} ]; # the values of x to use are given by A006880.
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CROSSREFS
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Cf. A055737, A006880.
Sequence in context: A053564 A036781 A084816 this_sequence A053365 A101034 A084168
Adjacent sequences: A055735 A055736 A055737 this_sequence A055739 A055740 A055741
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KEYWORD
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more,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 09 2000
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EXTENSIONS
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2 more terms from Jud McCranie (j.mccranie(AT)comcast.net), Oct 08 2000.
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