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A143430
a(n)=least prime == 1 mod 6 such that q(n)*(q(n)+a(n))-1 and q(n)*(q(n)+a(n))+1 are twin primes with q(i)=i-th prime == -1 mod 6.
4
7, 7, 43, 13, 43, 97, 43, 67, 193, 157, 31, 211, 61, 523, 73, 241, 13, 19, 97, 67, 13, 67, 157, 283, 193, 79, 157, 67, 151, 211, 67, 13, 7, 739, 109, 7, 151, 157, 73, 109, 61, 97, 223, 79, 157, 373, 109, 211, 193, 163, 67, 13, 31, 229, 19, 151, 31, 43, 31, 199, 7, 31
OFFSET
1,1
EXAMPLE
q(1)=5, 5*(5+7)-1=59 prime, 59 and 61 twin primes so a(1)=7
q(2)=11, 11*(11+7)-1=197 prime, 197 and 199 twin primes so a(2)=7
CROSSREFS
KEYWORD
nonn
AUTHOR
Pierre CAMI, Aug 14 2008
STATUS
approved