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A152866 Beginnings of maximal chains of primes with three members (two links). 8


%S 5,43,139,227,277,773,947,991,1237,1481,1549,1601,1871,1993,2339,3119,

%T 3169,3217,3259,3371,3709,3853,4013,4219,4483,4951,5051,5107,5147,

%U 5419,5527,6637,6977,7477,7699,8539,10139,10267,11783,11981,12163,12263

%N Beginnings of maximal chains of primes with three members (two links).

%C For definitions see A152658, of which this is a subsequence.

%H Klaus Brockhaus, <a href="/A152866/b152866.txt">Table of n, a(n) for n=1..1000</a>

%e First maximal chain of primes with three members (two links) is 5, 7, 11; the linking primes are 43, 83.

%o (PARI) {n=1; while(n<1470, c=0; a=prime(n); while(isprime(n*prime(n)+(n+1)*prime(n+1)), c++; n++); if(c==2, print1(a, ",")); n++)}

%Y Cf. A152658 (beginnings of maximal chains of primes), A152735 (count of links in n-th maximal chain of primes), A152962 (beginning of the first maximal chain of primes with n links), A152865, A152867, A152868, A152869, A152963, A152964.

%K nonn

%O 1,1

%A _Klaus Brockhaus_, Dec 17 2008

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Last modified May 14 07:13 EDT 2021. Contains 343879 sequences. (Running on oeis4.)