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 A109907 #11 Dec 31 2024 15:39:04
%S A109907 7,11,29,197,9689,23469167,137700449916401,
%T A109907 4740353476794815041972197893,
%U A109907 5617737771240172767652929826457529708578746492288409399,7889744416604625924469156192031986939513870147397674409917489724005347434748024264638497225986334149357868007
%N A109907 Beginning with 7, a(n+1) = greatest prime of the form k*{a(n)-k}-1. If no prime is obtained the sequence ends at that point.
%C A109907 Conjecture: The sequence is infinite.
%o A109907 (PARI) { b(n) = forstep(k=n\2,1,-1,if(isprime(k*(n-k)-1),return(k*(n-k)-1)));return(0) }
%o A109907 my(s=7); while(1,print1(s,", ");s=b(s)) \\ _Max Alekseyev_, Oct 04 2005
%Y A109907 Cf. A109904, A109905, A026728, A109908, A109909.
%K A109907 nonn
%O A109907 0,1
%A A109907 _Amarnath Murthy_, Jul 15 2005
%E A109907 More terms from _Max Alekseyev_, Oct 04 2005