A069457 Lowest primes in twin packs.
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
Offset: 1
Keywords
Examples
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 primes and the next primes are 149,151.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
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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
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