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 A086809 #10 Mar 23 2024 20:27:23
%S A086809 2,5,8,34,65,144,296,401,490,520,2165,3590,4640,4828,6828,8704,17675,
%T A086809 21164,52883,84762,162069,358838,1463826,1593474,1668393,2086706,
%U A086809 4364420,20471838,31960444
%N A086809 Indices k where A057176(k) = 2.
%C A086809 By definition of the sequence, A087045(n) + 1 for every n > 0 is in the sequence.
%C A086809 No more terms < 3870000. - _David Wasserman_, Mar 31 2005
%t A086809 a[m_] := a[m] = Sum[ a[j], {j, 0, Mod[ a[m - 1], m]}]; vv = {}; Do[ a[n] = If[ n == 0, 1, b]; v = a[n + 1]; b = v; If[ v == 2, AppendTo[ vv, n + 1]; Print[n + 1]], {n, 0, 165000}]
%Y A086809 Cf. A057176, A087045.
%K A086809 nonn,more
%O A086809 1,1
%A A086809 _Farideh Firoozbakht_, Aug 05 2003
%E A086809 Extended by _Robert G. Wilson v_, Aug 07 2003
%E A086809 More terms from _David Wasserman_, Mar 31 2005
%E A086809 a(27)-a(29) from _Michael S. Branicky_, Mar 23 2024