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%I #16 Aug 29 2022 04:42:08
%S 1,63,2268,61236,1377810,27280638,491051484,8207574804,129269303163,
%T 1939039547445,27922169483208,388371993720984,5243021915233284,
%U 68965903654222428,886704475554288360,11172476391984033336,138259395350802412533,1683511461036241140843
%N a(n) = binomial(n + 6, 6)*9^n.
%C Number of n-permutations (n>=6) of 10 objects p, r, q, u, v, w, z, x, y, z with repetition allowed, containing exactly six (6) u's.
%H Vincenzo Librandi, <a href="/A173191/b173191.txt">Table of n, a(n) for n = 0..400</a>
%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (63,-1701,25515,-229635,1240029,-3720087,4782969).
%F a(n) = C(n + 6, 6)*9^n.
%F From _Amiram Eldar_, Aug 29 2022: (Start)
%F Sum_{n>=0} 1/a(n) = 1042074/5 - 1769472*log(9/8).
%F Sum_{n>=0} (-1)^n/a(n) = 5400000*log(10/9) - 2844729/5. (End)
%p A173191:=n->binomial(n+6,6)*9^n: seq(A173191(n), n=0..25); # _Wesley Ivan Hurt_, Jul 24 2017
%t Table[Binomial[n + 6, 6]*9^n, {n, 0, 20}]
%o (Magma) [Binomial(n+6, 6)*9^n: n in [0..20]]; // _Vincenzo Librandi_, Oct 13 2011
%Y Cf. A081139, A173000, A173187, A173188.
%K nonn,easy
%O 0,2
%A _Zerinvary Lajos_, Feb 12 2010