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 A073608 #8 Oct 19 2017 03:14:04
%S A073608 1,3,5,8,10,12
%N A073608 a(1) = 1, a(n) = smallest number such that a(n) - a(n-k) is a prime power > 1 for all k.
%C A073608 Differences |a(i)-a(j)| are prime powers for all i,j. Conjecture: sequence is bounded.
%C A073608 Proof that sequence is complete: Assume there is some k after the term 12. Then {k-1, k-3, k-5} must contain a multiple of 3. Also {k-8,k-10,k-12} also contains a multiple of 3. No prime > 12 is a multiple of 3, so the multiples of 3 are both prime powers. This implies there must be two powers of 3 that have a difference at most 11, but no such pair exists > 12 (only 1,3 and 3,9 qualify.) - _Jim Nastos_, Aug 09 2002
%C A073608 There is an elementary proof that no set of seven integers of this kind exists. - _Don Reble_, Aug 10 2002
%e A073608 a(5) = 10 as 10-8, 10-5, 10-3, 10-1 or 2, 5, 7, 9 are prime powers.
%Y A073608 Cf. A073607.
%K A073608 nonn,fini,full
%O A073608 1,2
%A A073608 _Amarnath Murthy_, Aug 04 2002
%E A073608 Sixth term from _Jim Nastos_, Aug 09 2002