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 A227616 #18 Apr 06 2016 00:11:24
%S A227616 1,3,3,5,12,30,58,128,237,476,975,1956,3899,7798,15534,31270,62262,
%T A227616 124635,248944,497797,995730,1990576,3983767,7969049,15935289,
%U A227616 31870309,63739461,127519282,254994762,510016513,1020092276,2040066241,4080236749
%N A227616 Number of bits set to 1 in the binary representation of the n-th term of the Lucas-Lehmer sequence (A003010).
%F A227616 a(n) = A000120(A003010(n)).
%e A227616 For n = 2, A003010(2) = 11000010 (in binary), so a(2) = 3.
%p A227616 read("transforms") :
%p A227616 A227616 := proc(n)
%p A227616 wt(A003010(n)) ;
%p A227616 end proc: # _R. J. Mathar_, Jul 20 2013
%t A227616 First@ DigitCount[#, 2] & /@ NestList[#^2 - 2 &, 4, 28] (* _Michael De Vlieger_, Apr 04 2016 *)
%o A227616 (PARI) lista(nn) = {a = 4; print1(hammingweight(a), ", "); for (n=1, nn, a = a^2-2; print1(hammingweight(a), ", "););} \\ _Michel Marcus_, Apr 04 2016
%Y A227616 Cf. A003010, A227608, A227615.
%K A227616 nonn,base
%O A227616 0,2
%A A227616 _Olivier de Mouzon_, Jul 17 2013
%E A227616 Terms from a(19) on from _Michel Marcus_, Apr 04 2016