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A080840
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Number of cousin primes < 10^n.
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2
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1, 8, 41, 203, 1216, 8144, 58622, 440258, 3424680, 27409999, 224373161, 1870585459
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OFFSET
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1,2
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COMMENTS
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The corresponding numbers for twin primes and sexy primes are in A007508 and A080841, the greater of twin primes, cousin primes and sexy primes are in A006512, A046132 and A046117 respectively.
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LINKS
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Table of n, a(n) for n=1..12.
Eric Weisstein's World of Mathematics, Cousin Primes.
A. Granville, G. Martin, Prime number races, Amer. Math. Monthly vol 113, no 1 (2006) p 1.
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PROG
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(PARI) {c=0; p=5; for(n=1, 9, while(p<10^n, if(isprime(p-4), c++); p=nextprime(p+1)); print1(c, ", "))}
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CROSSREFS
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Cf. A007508, A080841, A006512, A046132, A046117.
Sequence in context: A078797 A176177 A156790 * A199846 A188180 A026968
Adjacent sequences: A080837 A080838 A080839 * A080841 A080842 A080843
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KEYWORD
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nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Mar 28 2003
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EXTENSIONS
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a(8) and a(9) from Klaus Brockhaus, Mar 30 2003
More terms from R. J. Mathar, Aug 05 2007
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STATUS
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approved
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