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 A180583 #21 Feb 18 2025 16:29:20 %S A180583 1,7,126,1484,18452,229698,2861964,35663964,444486280,5539931796, %T A180583 69048910000,860620499760,10726732430288,133697577587000, %U A180583 1666401898058352,20769976722986288,258876295158900832,3226625529605854320,40216553455854426560,501257787787122948736 %N A180583 Number of Hamiltonian cycles in C_7 X P_n. %H A180583 Andrew Howroyd, <a href="/A180583/b180583.txt">Table of n, a(n) for n = 1..500</a> %H A180583 Artem M. Karavaev, FlowProblem.ru web-project: <a href="https://web.archive.org/web/20161024010518/http://flowproblem.ru/cycles/hamilton-cycles">Hamilton Cycles</a> page. %H A180583 <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (12,18,-112,-440,-772,-196,2064,3724,2040,496,128,-16). %F A180583 a(n) = -16a(n-12) + 128a(n-11) + 496a(n-10) + 2040a(n-9) + 3724a(n-8) + 2064a(n-7) - 196a(n-6) - 772a(n-5) - 440a(n-4) - 112a(n-3) + 18a(n-2) + 12a(n-1) for n > 13. %F A180583 G.f.: x*(16*x^12 -16*x^11 +8*x^10 -192*x^9 +588*x^8 +1996*x^7 +700*x^6 -474*x^5 -400*x^4 -42*x^3 +24*x^2 -5*x +1)/(16*x^12 -128*x^11 -496*x^10 -2040*x^9 -3724*x^8 -2064*x^7 +196*x^6 +772*x^5 +440*x^4 +112*x^3 -18*x^2 -12*x +1). - _Colin Barker_, Sep 01 2012 %Y A180583 Column k=7 of A359855. %Y A180583 Cf. A003699, A003731, A180582, A180584, A180585, A180586, A180587, A180588. %K A180583 nonn,easy %O A180583 1,2 %A A180583 _Artem M. Karavaev_, Sep 10 2010 %E A180583 a(18) onwards from _Andrew Howroyd_, Feb 18 2025