This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A084961 #14 Mar 23 2017 10:06:21
%S A084961 2,2,2,2,11,13,115571,23586221,53165771,3398453717,615502598677,
%T A084961 32504183957101,164289842304587
%N A084961 Initial prime of the first prime chain of length n under the iteration x->6x+5.
%C A084961 This is a special case of prime chains generated by f(x) = cx + d.
%C A084961 a(11) > 10175130529. [_Donovan Johnson_, Sep 27 2008]
%H A084961 D. H. Lehmer, <a href="http://dx.doi.org/10.1112/plms/s3-14A.1.183">On certain chains of primes</a>, Proc. London Math. Soc. (3) 14a 1965 183-186.
%e A084961 a(3) = 2 since 2, f(2) = 17, and f(17) = 107 are primes when f(x) = 6*x + 5.
%t A084961 c[p_] := Block[{k=1, q=6*p+5}, While[ PrimeQ[q], q = 6*q+5; k++]; k]; a[n_] := Block[ {p=2}, While[c[p] < n, p = NextPrime[p]]; p]; Array[a, 7] (* _Giovanni Resta_, Mar 22 2017 *)
%Y A084961 Cf. A057330, A057331, A083388, A084954, A084955, A084956, A084957, A084958, A084959, A084960.
%K A084961 more,nonn
%O A084961 1,1
%A A084961 _W. Edwin Clark_, Jun 14 2003
%E A084961 a(8)-a(10) from _Donovan Johnson_, Sep 27 2008
%E A084961 a(11)-a(12) from _John Cerkan_, Jan 11 2017
%E A084961 a(13) from _Giovanni Resta_, Mar 22 2017