cp's OEIS Frontend

A290509 Number of irredundant sets in the n-Moebius ladder.

%I A290509 #16 Feb 16 2025 08:33:49
%S A290509 3,5,24,81,198,542,1550,4497,12732,36210,103579,296250,846303,2417308,
%T A290509 6907329,19737889,56396602,161138306,460420182,1315565326,3758963099,
%U A290509 10740463167,30688703123,87686813826,250547405698,715888629071,2045507376543,5844625042904
%N A290509 Number of irredundant sets in the n-Moebius ladder.
%H A290509 Andrew Howroyd, <a href="/A290509/b290509.txt">Table of n, a(n) for n = 1..200</a>
%H A290509 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/IrredundantSet.html">Irredundant Set</a>
%H A290509 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/MoebiusLadder.html">Moebius Ladder</a>
%F A290509 Empirical: a(n) = 3*a(n-1) - a(n-3) + 2*a(n-4) - 6*a(n-5) - 8*a(n-6) + 13*a(n-7) + 6*a(n-8) - 6*a(n-9) - 2*a(n-10) - 5*a(n-11) - 4*a(n-12) + 2*a(n-13) + 2*a(n-14) - a(n-15) + a(n-16) + 3*a(n-17) + 2*a(n-19) for n > 19. - _Andrew Howroyd_, Aug 05 2017
%F A290509 Empirical g.f.: x*(3 - 4*x + 9*x^2 + 12*x^3 - 46*x^4 - 20*x^5 + 11*x^6 + 28*x^7 - 18*x^8 - 8*x^9 + 21*x^10 - 4*x^11 + 18*x^12 + 8*x^13 - 15*x^14 + 4*x^15 + 23*x^16 + 14*x^18) / ((1 - x)*(1 - x^2 + x^4 + x^6)*(1 - 2*x - x^2 - 3*x^3 - 5*x^4 + 2*x^5 + 6*x^6 + 5*x^7 + 4*x^8 + 4*x^9 + 3*x^10 + 2*x^11 + 2*x^12)). - _Colin Barker_, Aug 05 2017
%Y A290509 Cf. A284663, A290337.
%K A290509 nonn
%O A290509 1,1
%A A290509 _Eric W. Weisstein_, Aug 04 2017
%E A290509 a(1)-a(2) and terms a(10) and beyond from _Andrew Howroyd_, Aug 05 2017