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A185313 Start of a sequence of n consecutive primes such that the sum of any three consecutive members is also prime. 0
2, 2, 5, 5, 5, 17, 17, 53507, 364187, 155650237, 15644021363, 604394270371, 767783880089 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(14) > 1.8*10^14. - Giovanni Resta, Jun 07 2017

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

Vacuously, the sum of every three consecutive members of {2, 3} is prime, so a(2) = 2.  a(4) = 5 because 5 + 7 + 11 and 7 + 11 + 13 are prime.

PROG

(PARI) a(n)=if(n<3, return(2), n-=2); my(len=0, p=2, q=3); forprime(r=5, default(primelimit), if(isprime(p+q+r), if(len++==n, my(t=p); for(i=2, n, t=precprime(t-1)); return(t)), len=0); p=q; q=r) \\ Charles R Greathouse IV, Feb 08 2012

CROSSREFS

Cf. A072225.

Sequence in context: A025510 A172417 A158106 * A208301 A069896 A053246

Adjacent sequences:  A185310 A185311 A185312 * A185314 A185315 A185316

KEYWORD

nonn,more

AUTHOR

Charles R Greathouse IV, Feb 08 2012

EXTENSIONS

a(11) from Charles R Greathouse IV, Feb 10 2012

a(12) from Charles R Greathouse IV, Feb 12 2012

a(13) from Zak Seidov, Jun 03 2017

STATUS

approved

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Last modified May 10 14:44 EDT 2021. Contains 343773 sequences. (Running on oeis4.)