A089629 Smallest member of a pair of consecutive twin prime pairs that have one prime between them.
17, 29, 59, 227, 269, 617, 1031, 1277, 1289, 1301, 1607, 1667, 1697, 2087, 2129, 2309, 2711, 2789, 3257, 3527, 3539, 3557, 3917, 4019, 4241, 4517, 4637, 4787, 5477, 5501, 5639, 6551, 7307, 8819, 8837, 8999, 9011, 10037, 10067, 10271, 10499, 12041, 13679
Offset: 1
Examples
Twin prime pairs 17,19 and 29,31 have only the prime 23 between them.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
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PARI
pbetweentw(n,p) = \p is the number of primes between { forstep(x1=1,n,1, c=0; t1 = twin[x1]; t2 = twin[x1+1]; for(y=t1+4,t2-1, if(isprime(y),c++) ); if(c==p,print1(t1",")) ) } \ build a twin prime table of lower bounds savetwins(n) = { twin = vector(n); c=1; forprime(x=3,n*10, if(isprime(x+2), twin[c]=x; c++; ) ) }
Extensions
Offset corrected by Amiram Eldar, Dec 28 2019
Comments