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 A369844 #17 Mar 15 2024 11:23:13
%S A369844 0,1,4,11,29,81,235,685,1986,5739,16577,47904,138472,400285,1157071,
%T A369844 3344567,9667590,27944604,80775310,233485250,674901117,1950836005,
%U A369844 5638990526,16299788815,47115369056,136189372297,393662311506,1137900943868,3289160582291,9507486039274
%N A369844 Number of compositions of 5*n-4 into parts 2 and 5.
%H A369844 Paolo Xausa, <a href="/A369844/b369844.txt">Table of n, a(n) for n = 1..1000</a>
%H A369844 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-9,10,-5,1).
%F A369844 a(n) = A001687(5*n-3).
%F A369844 a(n) = Sum_{k=0..floor(n/2)} binomial(n+1+3*k,n-2-2*k).
%F A369844 a(n) = 5*a(n-1) - 9*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5).
%F A369844 G.f.: x^2*(1-x)/((1-x)^5 - x^2).
%t A369844 LinearRecurrence[{5, -9, 10, -5, 1}, {0, 1, 4, 11, 29}, 50] (* _Paolo Xausa_, Mar 15 2024 *)
%o A369844 (PARI) a(n) = sum(k=0, n\2, binomial(n+1+3*k, n-2-2*k));
%Y A369844 Cf. A369803, A369840, A369842, A369843.
%Y A369844 Cf. A001687.
%K A369844 nonn,easy
%O A369844 1,3
%A A369844 _Seiichi Manyama_, Feb 03 2024