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Number of n-tuples of elements e_1,e_2,...,e_n in the symmetric group S_3 such that the subgroup generated by e_1,e_2,...,e_n is S_3.
1

%I #13 May 15 2019 08:33:26

%S 0,18,168,1170,7440,45738,277368,1672290,10056480,60404058,362613768,

%T 2176238610,13059075120,78359331978,470170537368,2821066664130,

%U 16926529911360,101559568461498,609358576176168,3656154950132850,21936940173733200,131621672448624618,789730128885258168

%N Number of n-tuples of elements e_1,e_2,...,e_n in the symmetric group S_3 such that the subgroup generated by e_1,e_2,...,e_n is S_3.

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (12,-47,72,-36)

%F a(n) = 6^n - 3*2^n - 3^n + 3.

%F G.f.: 6*x^2*(3 - 8*x) / (1 - 12*x + 47*x^2 - 72*x^3 + 36*x^4). [Corrected by _Georg Fischer_, May 15 2019]

%t LinearRecurrence[{12, -47, 72, -36}, {0, 18, 168, 1170, 7440}, 23] (* _Georg Fischer_, May 15 2019 *)

%o (PARI) a(n) = 6^n - 3*2^n - 3^n + 3; \\ _Michel Marcus_, Oct 31 2017

%K nonn,easy

%O 1,2

%A Sharon Sela (sharonsela(AT)hotmail.com), Jun 02 2002

%E More terms from _Michel Marcus_, Oct 31 2017