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 A117602 #16 Oct 13 2024 05:12:18
%S A117602 1,2,3,4,5,7,9,12,21,28,37,114,200,351,616,816,1081,1432,1897,4410,
%T A117602 5842,10252,13581,17991,23833,31572,41824,55405,73396,170625,396655,
%U A117602 525456,696081,1221537,1618192,2143648,3761840,11584946,20330163,26931732,62608681
%N A117602 Padovan numbers which can be divided by their digital root.
%H A117602 Nathaniel Johnston, <a href="/A117602/b117602.txt">Table of n, a(n) for n = 1..1000</a>
%H A117602 Kevin Ryde, <a href="/A117602/a117602.gp.txt">PARI/GP Code</a>, finding linear recurrence and g.f.
%H A117602 <a href="/index/Rec#order_8544">Index entries for linear recurrences with constant coefficients</a>, order 8544.
%F A117602 a(n) = X*a(n-s) + Y*a(n-2*s) + a(n-3*s) for n >= 8546, where s = 2848, X = Perrin(f) = A001608(f), Y = -Perrin(-f) = A078712(f), f = 4368. - _Kevin Ryde_, Oct 12 2024
%p A117602 A000931 := proc(n) option remember: if(n=0)then return 1: elif(n<=2)then return 0: else return procname(n-2)+procname(n-3): fi: end: A117602ind := proc(n) option remember: local k,p: if(n=1)then return 7: fi: for k from procname(n-1)+1 do p:=A000931(k): if(not p=A000931(A117602ind(n-1)) and p mod (((p-1) mod 9) + 1) = 0)then return k: fi: od: end: seq(A000931(A117602ind(n)),n=1..41); # _Nathaniel Johnston_, May 05 2011
%t A117602 p=LinearRecurrence[{0, 1, 1}, {1, 0, 0}, 71];Rest[Union[Select[p,Divisible[#,Mod[#-1,9]+1]&]]] (* _James C. McMahon_, Sep 25 2024 *)
%o A117602 (PARI) \\ See links.
%Y A117602 Cf. A000931, A117601, A117603, A117604.
%K A117602 nonn,easy,base
%O A117602 1,2
%A A117602 Luc Stevens (lms022(AT)yahoo.com), Apr 05 2006
%E A117602 Offset changed from 0 to 1 by _Nathaniel Johnston_, May 05 2011