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A023201 Numbers n such that n and n + 6 both prime. 78
5, 7, 11, 13, 17, 23, 31, 37, 41, 47, 53, 61, 67, 73, 83, 97, 101, 103, 107, 131, 151, 157, 167, 173, 191, 193, 223, 227, 233, 251, 257, 263, 271, 277, 307, 311, 331, 347, 353, 367, 373, 383, 433, 443, 457, 461, 503, 541, 557, 563, 571, 587, 593, 601, 607, 613, 641, 647 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

Eric Weisstein's World of Mathematics, Sexy Primes.

Eric Weisstein's World of Mathematics, Twin Primes

MAPLE

A023201 := proc(n)

    option remember;

    if n = 1 then

        5;

    else

        for a from procname(n-1)+2 by 2 do

            if isprime(a) and isprime(a+6) then

                return a;

            end if;

        end do:

    end if;

end proc: # R. J. Mathar, May 28 2013

MATHEMATICA

Select[Range[10^2], PrimeQ[ # ]&&PrimeQ[ #+6] &] (from Vladimir Joseph Stephan Orlovsky, Apr 29 2008)

PROG

(MAGMA) [n: n in [0..40000] | IsPrime(n) and IsPrime(n+6)] [From Vincenzo Librandi, Aug 04 2010]

(Haskell)

a023201 n = a023201_list !! (n-1)

a023201_list = filter ((== 1) . a010051 . (+ 6)) a000040_list

-- Reinhard Zumkeller, Feb 25 2013

(PARI) is(n)=isprime(n+6)&&isprime(n) \\ Charles R Greathouse IV, Mar 20 2013

CROSSREFS

A031924 and A007529 together give A023201.

Cf. A046117, A098428, A000040, A010051, A006489 (subsequence).

Sequence in context: A040146 A243593 A015914 * A106059 A102386 A038958

Adjacent sequences:  A023198 A023199 A023200 * A023202 A023203 A023204

KEYWORD

nonn,easy

AUTHOR

David W. Wilson

STATUS

approved

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Last modified December 17 18:04 EST 2014. Contains 252034 sequences.