%I #16 May 03 2021 07:39:08
%S 3,5,10,19,37,71,137,264,509,981,1891,3645,7026,13543,26105,50319,
%T 96993,186960,360377,694649,1338979,2580965,4974970,9589563,18484477,
%U 35629975,68678985,132383000,255176437,491868397,948106819,1827534653,3522686306,6790196175
%N Tetranacci numbers arising in connection with current algebras sp(2)_n.
%H Noureddine Chair, <a href="https://arxiv.org/abs/hep-th/9704138">Grassmannian Cohomology Rings and Fusion Rings From Algebraic Equations</a>, arXiv:hep-th/9704138, 1997.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,1,1).
%F G.f.: (3+2x+2x^2+x^3)/(1-x-x^2-x^3-x^4).
%t LinearRecurrence[{1, 1, 1, 1}, {3, 5, 10, 19}, 29] (* _Jean-François Alcover_, Feb 24 2019 *)
%o (PARI) my(p=Mod('x,'x^4-'x^3-'x^2-'x-1)); a(n) = -subst(lift(p^(n+7)),'x,-1); \\ _Kevin Ryde_, May 03 2021
%K easy,nonn
%O 0,1
%A _Noureddine Chair_