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 A369843 #16 Mar 15 2024 11:35:07
%S A369843 1,2,4,11,34,102,296,851,2452,7085,20489,59241,171245,494973,1430710,
%T A369843 4135527,11953991,34553692,99879234,288705927,834519021,2412219633,
%U A369843 6972643768,20154781952,58258423000,168398935968,486765693153,1407021006061,4067065818560
%N A369843 Number of compositions of 5*n-3 into parts 2 and 5.
%H A369843 Paolo Xausa, <a href="/A369843/b369843.txt">Table of n, a(n) for n = 1..1000</a>
%H A369843 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-9,10,-5,1).
%F A369843 a(n) = A001687(5*n-2).
%F A369843 a(n) = Sum_{k=0..floor(n/2)} binomial(n+3*k,n-1-2*k).
%F A369843 a(n) = 5*a(n-1) - 9*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5).
%F A369843 G.f.: x*(1-x)^3/((1-x)^5 - x^2).
%t A369843 LinearRecurrence[{5, -9, 10, -5, 1}, {1, 2, 4, 11, 34}, 50] (* _Paolo Xausa_, Mar 15 2024 *)
%o A369843 (PARI) a(n) = sum(k=0, n\2, binomial(n+3*k, n-1-2*k));
%Y A369843 Cf. A369803, A369840, A369842, A369844.
%Y A369843 Cf. A001687.
%K A369843 nonn,easy
%O A369843 1,2
%A A369843 _Seiichi Manyama_, Feb 03 2024