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 A369845 #17 Mar 15 2024 20:43:06
%S A369845 1,1,1,2,7,22,58,138,319,750,1810,4427,10828,26349,63862,154603,
%T A369845 374521,908140,2203162,5344988,12964858,31443013,76253683,184929945,
%U A369845 448506736,1087774536,2638209313,6398479259,15518219326,37636240539,91279009255,221378866489
%N A369845 Number of compositions of 5*n into parts 3 and 5.
%H A369845 Paolo Xausa, <a href="/A369845/b369845.txt">Table of n, a(n) for n = 0..1000</a>
%H A369845 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,11,-5,1).
%F A369845 a(n) = A052920(5*n).
%F A369845 a(n) = Sum_{k=0..floor(n/3)} binomial(n+2*k,n-3*k).
%F A369845 a(n) = 5*a(n-1) - 10*a(n-2) + 11*a(n-3) - 5*a(n-4) + a(n-5).
%F A369845 G.f.: (1-x)^4/((1-x)^5 - x^3).
%F A369845 a(n) = A369847(n+1)-A369847(n). - _R. J. Mathar_, Feb 14 2024
%t A369845 LinearRecurrence[{5, -10, 11, -5, 1}, {1, 1, 1, 2, 7}, 50] (* _Paolo Xausa_, Mar 15 2024 *)
%o A369845 (PARI) a(n) = sum(k=0, n\3, binomial(n+2*k, n-3*k));
%Y A369845 Cf. A369804, A369846, A369847, A369848.
%Y A369845 Cf. A052920.
%K A369845 nonn,easy
%O A369845 0,4
%A A369845 _Seiichi Manyama_, Feb 03 2024