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 A373934 #15 Jun 24 2024 05:41:34
%S A373934 0,1,3,6,10,15,21,29,46,100,275,781,2080,5097,11562,24583,49725,97376,
%T A373934 188480,368734,742811,1553192,3353332,7372536,16261025,35583926,
%U A373934 76806997,163327279,342902007,713848316,1481274767,3078928619,6433465844,13534471164
%N A373934 Number of compositions of 7*n-2 into parts 6 and 7.
%H A373934 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (7,-21,35,-35,21,-6,1).
%F A373934 a(n) = A017847(7*n-2).
%F A373934 a(n) = Sum_{k=0..floor(n/6)} binomial(n+k,n-2-6*k).
%F A373934 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 A373934 G.f.: x^2*(1-x)^4/((1-x)^7 - x^6).
%F A373934 a(n) = A373935(n+1)-A373935(n). - _R. J. Mathar_, Jun 24 2024
%o A373934 (PARI) a(n) = sum(k=0, n\6, binomial(n+k, n-2-6*k));
%Y A373934 Cf. A369809, A373912, A373933, A373935, A373936, A373937.
%Y A373934 Cf. A017847, A369850.
%K A373934 nonn,easy
%O A373934 1,3
%A A373934 _Seiichi Manyama_, Jun 23 2024