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A080840
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Number of cousin primes < 10^n.
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3
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1, 8, 41, 203, 1216, 8144, 58622, 440258, 3424680, 27409999, 224373161, 1870585459, 15834656003, 135779962760, 1177207270204
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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.
In this sequence, only the upper member of each prime cousin pair is counted. See A152052 for the variant where only the lower member is counted. - James Rayman, Jan 17 2021
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LINKS
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A. Granville and 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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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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