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 A369846 #16 Mar 15 2024 11:23:31
%S A369846 0,1,4,10,21,44,101,250,629,1557,3784,9120,21992,53228,129177,313701,
%T A369846 761403,1846804,4478044,10858285,26332515,63865592,154900529,
%U A369846 375691009,911166977,2209835169,5359470121,12998281146,31524747503,76457088518,185431544730
%N A369846 Number of compositions of 5*n-1 into parts 3 and 5.
%H A369846 Paolo Xausa, <a href="/A369846/b369846.txt">Table of n, a(n) for n = 1..1000</a>
%H A369846 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,11,-5,1).
%F A369846 a(n) = A052920(5*n-1).
%F A369846 a(n) = Sum_{k=0..floor(n/3)} binomial(n+1+2*k,n-2-3*k).
%F A369846 a(n) = 5*a(n-1) - 10*a(n-2) + 11*a(n-3) - 5*a(n-4) + a(n-5).
%F A369846 G.f.: x^2*(1-x)/((1-x)^5 - x^3).
%t A369846 LinearRecurrence[{5, -10, 11, -5, 1}, {0, 1, 4, 10, 21}, 50] (* _Paolo Xausa_, Mar 15 2024 *)
%o A369846 (PARI) a(n) = sum(k=0, n\3, binomial(n+1+2*k, n-2-3*k));
%Y A369846 Cf. A369804, A369845, A369847, A369848.
%Y A369846 Cf. A052920.
%K A369846 nonn,easy
%O A369846 1,3
%A A369846 _Seiichi Manyama_, Feb 03 2024