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 A023442 #16 Jul 08 2025 17:15:46
%S A023442 0,1,1,2,3,5,8,13,21,34,55,89,144,232,375,605,977,1577,2546,4110,6635,
%T A023442 10711,17291,27913,45060,72741,117426,189562,306011,493996,797461,
%U A023442 1287347,2078173,3354809,5415691,8742587
%N A023442 Dying rabbits: a(n) = a(n-1) + a(n-2) - a(n-12).
%H A023442 J. H. E. Cohn, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/2-2/cohn1.pdf">Letter to the editor</a>, Fib. Quart. 2 (1964), 108.
%H A023442 V. E. Hoggatt, Jr. and D. A. Lind, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/7-5/hoggatt.pdf">The dying rabbit problem</a>, Fib. Quart. 7 (1969), 482-487.
%H A023442 <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1).
%F A023442 G.f.: x/ ( (x-1)*(x^11+x^10+x^9+x^8+x^7+x^6+x^5+x^4+x^3+x^2-1) ). - _R. J. Mathar_, Nov 29 2011
%t A023442 LinearRecurrence[{1,1,0,0,0,0,0,0,0,0,0,-1},{0,1,1,2,3,5,8,13,21,34,55,89},40] (* _Harvey P. Dale_, Aug 29 2021 *)
%o A023442 (PARI) concat(0, Vec(x/ ( (x-1)*(x^11+x^10+x^9+x^8+x^7+x^6+x^5+x^4+x^3+x^2-1) ) + O(x^50))) \\ _Michel Marcus_, Sep 06 2017
%Y A023442 See A000045 for the Fibonacci numbers.
%K A023442 nonn
%O A023442 0,4
%A A023442 _N. J. A. Sloane_