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 A099464 #30 Jan 19 2025 14:31:12
%S A099464 0,1,7,44,274,1705,10609,66012,410744,2555757,15902591,98950096,
%T A099464 615693474,3831006429,23837527729,148323355432,922906855808,
%U A099464 5742568741225,35731770264967,222332455004452,1383410902447554,8607945812375585,53560898629395777,333269972246340068
%N A099464 Trisection of tribonacci numbers.
%C A099464 Let A = [1,1,1; 2,4,3; 1,2,2]. a(n) is given by the (1,2) term in A^n.
%H A099464 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (7,-5,1).
%F A099464 G.f.: x/(1-7*x+5*x^2-x^3).
%F A099464 a(n) = 7a(n-1) -5a(n-2) +a(n-3).
%F A099464 a(n) = A000073(3n).
%F A099464 a(n) = Sum_{i>=n-1} A120987(i,n-1) for n>0. - _Alois P. Heinz_, Dec 11 2015
%p A099464 a:= n-> (<<0|1|0>, <0|0|1>, <1|-5|7>>^n)[3, 1]:
%p A099464 seq(a(n), n=0..30); # _Alois P. Heinz_, Dec 11 2015
%t A099464 LinearRecurrence[{7,-5,1},{0,1,7},30] (* _Harvey P. Dale_, Jan 14 2016 *)
%Y A099464 Cf. A009943, A120987.
%K A099464 easy,nonn
%O A099464 0,3
%A A099464 _Paul Barry_, Oct 16 2004