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A001097 Twin primes. 131
3, 5, 7, 11, 13, 17, 19, 29, 31, 41, 43, 59, 61, 71, 73, 101, 103, 107, 109, 137, 139, 149, 151, 179, 181, 191, 193, 197, 199, 227, 229, 239, 241, 269, 271, 281, 283, 311, 313, 347, 349, 419, 421, 431, 433, 461, 463, 521, 523, 569, 571, 599, 601, 617, 619, 641, 643 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Union of A001359 and A006512.

The only twin primes that are Fibonacci numbers are 3, 5 and 13 [MacKinnon]. - Emeric Deutsch, Apr 24 2005

(p, p+2) are twin primes if and only if p + 2 can be represented as the sum of two primes. Brun (1919): Even if there are infinitely many twin primes, the series of all twin prime reciprocals does converges against Brun's constant (A065421). Clement (1949): (n, n+2) are twin primes if and only if (4*(n-1)!+n+4) mod n(n+2) = 0. - Stefan Steinerberger, Dec 04 2005

A164292(a(n)) = 1. [From Reinhard Zumkeller, Mar 29 2010]

The 100355-digit numbers, 65516468355 ยท 2^333333 +/- 1, are currently the largest known twin primes. They were discovered by Twin Prime Search and Primegrid in August 2009. - Paul Muljadi, Mar 07 2011

REFERENCES

Harvey Dubner, Twin Prime Statistics, Journal of Integer Sequences, Vol. 8 (2005), Article 05.4.2.

N. MacKinnon, Problem 10844, Amer. Math. Monthly 109, (2002), p. 78.

P. Ribenboim, The New Book of Prime Number Records, Springer-Verlag, p. 259-265.

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972, p. 870.

J. P. Delahaye, Twin Primes: Enemy Brothers? (In French.)

Andrew Granville, Primes in intervals of bounded length

James Maynard, Small gaps between primes, Annals of Mathematics, to appear.

Omar E. Pol, Determinacion geometrica de los numeros primos y perfectos.

D. H. J. Polymath, New equidistribution estimates of Zhang type, and bounded gaps between primes.

D. H. J. Polymath, Variants of the Selberg sieve, and bounded intervals containing many primes. In preparation.

Eric Weisstein's World of Mathematics, Twin Primes

Yitang Zhang, Bounded gaps between primes, Annals of Mathematics.

Index entries for primes, gaps between

MATHEMATICA

Select[ Prime[ Range[120]], PrimeQ[ # - 2] || PrimeQ[ # + 2] &] (* Robert G. Wilson v, Jun 09 2005 *)

PROG

(PARI) isA001097(n) = (isprime(n) & (isprime(n+2) | isprime(n-2))) \\ Michael B. Porter, Oct 29 2009

(PARI) a(n)=if(n==1, return(3)); my(p); forprime(q=3, default(primelimit), if(q-p==2 && (n-=2)<0, return(if(n==-1, q, p))); p=q) \\ Charles R Greathouse IV, Aug 22 2012

(Haskell)

a001097 n = a001097_list !! (n-1)

a001097_list = filter ((== 1) . a164292) [1..]

-- Reinhard Zumkeller, Feb 03 2014, Nov 27 2011

CROSSREFS

Cf. A070076, A001359, A006512, A164292. See A077800 for another version.

Sequence in context: A045393 A132143 A239879 * A117243 A179679 A059362

Adjacent sequences:  A001094 A001095 A001096 * A001098 A001099 A001100

KEYWORD

nonn,core,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from James A. Sellers, Sep 19 2000

STATUS

approved

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Last modified October 26 02:56 EDT 2014. Contains 248566 sequences.