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 A178095 #14 Aug 19 2014 17:14:27
%S A178095 1,1,1,3,5,3,11,19,3,3,5,11,19,5,5,29,3,37,3,43,83,3,3,89,5,97,191,
%T A178095 293,7,491,7,5,503,5,3,7,3,13,23,3,3,29,5,37,71,113,13,197,17,227,3,
%U A178095 13,3,19,5,3,3,11,17,31,59,107,197,3,307,3,313,7,17,337,19,373,3,5,3,11,19,3,3,5,11,19,5,5,29,3,37,3,43,83,3,3,89,5,97,191,293,7,491,7
%N A178095 a(1)=a(2)=a(3)=1; thereafter a(n) = lpf(a(n-1)+a(n-2)+a(n-3)), where lpf = "least prime factor".
%C A178095 Has period 69, starting with the fourth term: 3, 5, 3, 11, 19, 3, 3, 5, 11, ...
%t A178095 nxt[{a_,b_,c_}]:={b,c,FactorInteger[a+b+c][[1,1]]}; Transpose[ NestList[ nxt,{1,1,1},100]][[1]] (* _Harvey P. Dale_, Aug 19 2014 *)
%Y A178095 Cf. A178094, A020639, A175723, A177904.
%K A178095 nonn
%O A178095 1,4
%A A178095 _N. J. A. Sloane_, Dec 16 2010