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A080840 Number of cousin primes < 10^n. +0
3
1, 8, 41, 203, 1216, 8144, 58622, 440258, 3424680, 27409999, 224373161, 1870585459 (list; graph; listen)
OFFSET

1,2

COMMENT

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.

LINKS

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.

PROGRAM

(PARI) {c=0; p=5; for(n=1, 9, while(p<10^n, if(isprime(p-4), c++); p=nextprime(p+1)); print1(c, ", "))}

CROSSREFS

Cf. A007508, A080841, A006512, A046132, A046117.

Sequence in context: A133106 A078797 A156790 this_sequence A026968 A026978 A037577

Adjacent sequences: A080837 A080838 A080839 this_sequence A080841 A080842 A080843

KEYWORD

nonn

AUTHOR

Jason Earls (zevi_35711(AT)yahoo.com), Mar 28 2003

EXTENSIONS

a(8) and a(9) from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Mar 30 2003

More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 05 2007

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Last modified December 5 23:38 EST 2009. Contains 170428 sequences.


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