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 A080004 #24 Apr 16 2024 03:21:35
%S A080004 1,1,1,2,4,9,15,25,46,84,156,280,501,909,1647,2990,5408,9773,17695,
%T A080004 32033,58000,104976,189968,343860,622409,1126617,2039201,3690898,
%U A080004 6680644,12092173,21887215,39616409,71706406,129790404,234923948
%N A080004 Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=2, r=3, I={-1,2}.
%D A080004 D. H. Lehmer, Permutations with strongly restricted displacements. Combinatorial theory and its applications, II (Proc. Colloq., Balatonfured, 1969), pp. 755-770. North-Holland, Amsterdam, 1970.
%H A080004 Vladimir Baltic, <a href="http://pefmath.etf.rs/vol4num1/AADM-Vol4-No1-119-135.pdf">On the number of certain types of strongly restricted permutations</a>, Applicable Analysis and Discrete Mathematics Vol. 4, No 1 (2010), 119-135
%H A080004 K. Edwards and M. A. Allen, <a href="http://dx.doi.org/10.1016/j.dam.2015.02.004">Strongly restricted permutations and tiling with fences</a>, Discrete Applied Mathematics, Volume 187, 31 May 2015, Pages 82-90.
%H A080004 <a href="/index/Rec#order_10">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,1,1,4,-1,1,0,-1,-1).
%F A080004 a(n) = a(n-1)+a(n-3)+a(n-4)+4*a(n-5)-a(n-6)+a(n-7)-a(n-9)-a(n-10).
%F A080004 G.f.: -(x^5-1)/(x^10+x^9-x^7+x^6-4*x^5-x^4-x^3-x+1).
%t A080004 LinearRecurrence[{1,0,1,1,4,-1,1,0,-1,-1},{1,1,1,2,4,9,15,25,46,84},40] (* _Harvey P. Dale_, Jun 18 2013 *)
%Y A080004 Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
%K A080004 nonn
%O A080004 0,4
%A A080004 _Vladimir Baltic_, Feb 10 2003