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 A191903 #33 Aug 13 2022 06:22:34
%S A191903 0,8,40,128,312,648,1200,2048,3280,5000,7320,10368,14280,19208,25312,
%T A191903 32768,41760,52488,65160,80000,97240,117128,139920,165888,195312,
%U A191903 228488,265720,307328,353640,405000,461760,524288,592960,668168,750312
%N A191903 Number of compositions of odd natural numbers into 4 parts <= n.
%H A191903 Vincenzo Librandi, <a href="/A191903/b191903.txt">Table of n, a(n) for n = 0..10000</a>
%H A191903 Adi Dani, <a href="https://oeis.org/wiki/User:Adi_Dani_/Restricted_compositions_of_natural_numbers">Restricted compositions of natural numbers</a>.
%H A191903 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,0,5,-4,1).
%F A191903 a(n) = ((n + 1)^4 - (1 + (-1)^n)/2)/2.
%F A191903 From _R. J. Mathar_, Jun 22 2011: (Start)
%F A191903 G.f.: 8*x*(1+x+x^2) / ( (1+x)*(1-x)^5 ).
%F A191903 a(n) = 8*A011863(n+1). (End)
%F A191903 a(n) = floor((n+1)^4/2). - _Wesley Ivan Hurt_, Jun 14 2013
%F A191903 Sum_{n>=1} 1/a(n) = 3/4 + Pi^4/720 - tanh(Pi/2)*Pi/4. - _Amiram Eldar_, Aug 13 2022
%e A191903 a(1) = 8 compositions of odd numbers into 4 parts < 1.
%e A191903 1:(0,0,0,1),(0,0,1,1),(0,1,0,0),(1,0,0,0)
%e A191903 3:(0,1,1,1),(1,0,1,1),(1,1,0,1),(1,1,1,0)
%t A191903 Table[Floor[1/2*((n + 1)^4 - (1 + (-1)^n)/2)], {n, 0, 30}]
%o A191903 (Magma) [((n + 1)^4 - (1 + (-1)^n)/2)/2: n in [0..50]]; // _Vincenzo Librandi_, Jul 04 2011
%Y A191903 Cf. A011863, A171714.
%K A191903 nonn,easy
%O A191903 0,2
%A A191903 _Adi Dani_, Jun 19 2011