Cunningham chains of length n of the fi rst kind are n long sequences of prime numbers p(1,)p(2),...,p(n) so that p(i+1) = 2p(i) + 1 (for 1 <= i < n). In 3 we have devised a plan to fi nd large Cunningham chains of the fi rst kind of length 3 where the primes are of the form p(i+1) = (h(0) + cx) . 2(e+i) - 1 for some integer x with h(0) = 5 775, c = 30 030 and e = 34 944. The project was executed on the non-uniform memory access (NUMA) supercomputer of NIIF in Pecs, Hungary. In this paper we report on the obtained results and discuss the implementation details. The search consisted of two stages: sieving and the Fermat test. The sieving stage was implemented in a concurrent manner using lockfree queues, while the Fermat test was trivially parallel. On the 27th of April, 2014 we have found the largest known Cunningham chain of length 3 of the fi rst kind which consists of the numbers 5110664609396115 . 2(34944+j) 1 for j = 0, 1, 2.
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