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 A362196 #20 May 05 2023 16:03:54
%S A362196 1,1,2,5,12,27,58,121,248,502,1003,1970,3785,7086,12897,22804,39187,
%T A362196 65519,106744,169747,263930,401909,600348,880947,1271602,1807756,
%U A362196 2533961,3505672,4791295,6474512,8656907,11460918,15033141,19548013,25211902,32267633,40999480
%N A362196 Number of Grassmannian permutations of size n that avoid a pattern, sigma, where sigma is a pattern of size 9 with exactly one descent.
%C A362196 A permutation is said to be Grassmannian if it has at most one descent. The definition for sigma is a pattern of size 9 with exactly one descent. For example, sigma can be chosen to be 124793568, 248135679, 367912458, 591234678, etc.
%H A362196 Juan B. Gil and Jessica Tomasko, <a href="https://doi.org/10.54550/ECA2022V2S4PP6">Restricted Grassmannian permutations</a>, ECA 2:4 (2022) Article S4PP6.
%H A362196 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (9,-36,84,-126,126,-84,36,-9,1).
%F A362196 a(n) = 1 + Sum_{i=2..8} binomial(n,i).
%F A362196 G.f.: (1-8*x+29*x^2-61*x^3+81*x^4-69*x^5+37*x^6-11*x^7+2*x^8)/(1-x)^9.
%F A362196 a(n) = (n^8-20*n^7+210*n^6-1064*n^5+3969*n^4-4340*n^3+15980*n^2-14736*n+40320)/8!. - _Alois P. Heinz_, Apr 21 2023
%t A362196 Table[1 + Sum[Binomial[n, i-1],{i,3,9}],{n,0,36}] (* _Stefano Spezia_, Apr 20 2023 *)
%Y A362196 Cf. A000325, A362195.
%K A362196 nonn,easy
%O A362196 0,3
%A A362196 _Jessica A. Tomasko_, Apr 20 2023