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 A373936 #15 Jun 24 2024 05:44:54
%S A373936 0,0,0,1,5,15,35,70,126,211,342,573,1079,2366,5733,14197,34223,78832,
%T A373936 173166,364876,745066,1493990,2985725,6030652,12428911,26199706,
%U A373936 56231526,121847272,264270015,570020037,1218672066,2581172411,5424947523,11347651254
%N A373936 Number of compositions of 7*n-4 into parts 6 and 7.
%H A373936 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (7,-21,35,-35,21,-6,1).
%F A373936 a(n) = A017847(7*n-4).
%F A373936 a(n) = Sum_{k=0..floor(n/6)} binomial(n+k,n-4-6*k).
%F A373936 a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 6*a(n-6) + a(n-7).
%F A373936 G.f.: x^4*(1-x)^2/((1-x)^7 - x^6).
%F A373936 a(n) = A373937(n+1)-A373937(n). - _R. J. Mathar_, Jun 24 2024
%o A373936 (PARI) a(n) = sum(k=0, n\6, binomial(n+k, n-4-6*k));
%Y A373936 Cf. A369809, A373912, A373933, A373934, A373935, A373937.
%Y A373936 Cf. A017847, A369807.
%K A373936 nonn,easy
%O A373936 1,5
%A A373936 _Seiichi Manyama_, Jun 23 2024