A152868 - OEIS

%I #5 Mar 30 2012 17:27:56

%S 61,1069,2293,2879,5441,20347,145823,183949,187171,207629,219649,

%T 278087,412171,420467,421273,507503,536479,696937,698311,774929,

%U 792283,1028081,1310137,1432927,1470757,1726211,1803881,1861817,1904477,1928561

%N Beginnings of maximal chains of primes with five members (four links).

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

%H Klaus Brockhaus, <a href="/A152868/b152868.txt">Table of n, a(n) for n=1..1100</a>

%e First maximal chain of primes with five members (four links) is 61, 67, 71, 73, 79; the linking primes are 2371, 2693, 2953, 3271.

%o (PARI) {n=1; while(n<144100, c=0; a=prime(n); while(isprime(n*prime(n)+(n+1)*prime(n+1)), c++; n++); if(c==4, 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, A152866, A152867, A152869, A152963, A152964.

%K nonn

%O 1,1

%A _Klaus Brockhaus_, Dec 17 2008