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Number of ordered 3-multiantichains on an n-set.
4

%I #12 Sep 08 2022 08:45:13

%S 1,2,10,74,730,8282,92170,959114,9359290,86810042,775127530,

%T 6729173354,57217937050,479099439002,3966035935690,32552638110794,

%U 265489098246010,2154919024055162,17428334622452650,140575105877211434

%N Number of ordered 3-multiantichains on an n-set.

%H G. C. Greubel, <a href="/A092881/b092881.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (28,-315,1820,-5684,9072,-5760).

%F a(n) = 8^n - 6*6^n + 6*5^n + 6*4^n - 12*3^n + 6*2^n.

%F G.f.: -(4752*x^5-3852*x^4+1396*x^3-269*x^2+26*x-1) / ((2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(6*x-1)*(8*x-1)). - _Colin Barker_, Dec 10 2012

%t Table[8^n - 6*6^n + 6*5^n + 6*4^n - 12*3^n + 6*2^n, {n,0,50}] (* _G. C. Greubel_, Oct 07 2017 *)

%o (PARI) for(n=0,50, print1(8^n - 6*6^n + 6*5^n + 6*4^n - 12*3^n + 6*2^n , ", ")) \\ _G. C. Greubel_, Oct 07 2017

%o (Magma) [8^n - 6*6^n + 6*5^n + 6*4^n - 12*3^n + 6*2^n: n in [0..50]]; // _G. C. Greubel_, Oct 07 2017

%Y Cf. A092880, A092882-A092884.

%K nonn,easy

%O 0,2

%A Goran Kilibarda, _Vladeta Jovovic_, Mar 10 2004