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A069457 Lowest primes in twin packs. 3
3, 101, 137, 179, 419, 809, 1019, 1049, 1481, 1871, 1931, 2081, 2111, 2969, 3251, 3359, 3461, 4217, 4259, 5009, 5651, 5867, 6689, 6761, 6947, 7331, 7547, 8219, 8969, 9419, 10007, 11057, 11159, 11699, 12239, 13001, 13709, 13997 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

A twin pack of primes contains 2 or more pairs of twin primes, between which pairs there are no other primes. 137 is in the sequence because 137,139 are prime and the next primes are 149,151.

MAPLE

state:= 0: p:=13: Res:= 3: count:= 1;

while count < 100 do

  q:= nextprime(p);

  if state = 0 then

     if q = p+2 then state:= 1; r:= p; p:= nextprime(q);

     else p:= q

     fi;

   elif state = 1 then

     if q = p+2 then

       count:= count+1; Res:= Res, r; state:= 2; p:= nextprime(q);

     else p:= q; state:= 0

     fi

   else

     if q = p+2 then

       p:= nextprime(q);

     else p:= q; state:= 0

     fi

   fi

od:

Res; # Robert Israel, Jan 13 2020

CROSSREFS

Cf. A001359, A048614, A053778.

Sequence in context: A128296 A037114 A336437 * A142416 A110625 A108220

Adjacent sequences:  A069454 A069455 A069456 * A069458 A069459 A069460

KEYWORD

nonn

AUTHOR

Neil Fernandez, Mar 23 2002

STATUS

approved

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Last modified October 23 08:40 EDT 2021. Contains 348211 sequences. (Running on oeis4.)