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 A199805 #11 Jan 05 2025 19:51:39 %S A199805 1,-1,-4,10,8,-61,35,268,-512,-732,3525,-645,-17200,24682,57148, %T A199805 -197113,-46745,1064776,-1085312,-4088200,10626281,7664631,-63798924, %U A199805 40190250,275842720,-548257525,-726966901,3703906996,-893172736,-17805071620,26701809197,57726469171,-208147414040,-35978050998,1107739781172,-1193723409393,-4172806133425 %N A199805 G.f.: 1/(1 + x + 5*x^2 - x^3 + x^4). %H A199805 Michael D. Hirschhorn, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Papers1/43-4/paper43-4-5.pdf">Non-trivial intertwined second-order recurrence relations</a>, Fibonacci Quart. 43 (2005), no. 4, 316-325. See P_n. %K A199805 sign %O A199805 0,3 %A A199805 _N. J. A. Sloane_, Nov 10 2011