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%I #18 Feb 16 2024 17:05:46
%S 1,5,24,132,840,6120,50400,463680,4717440,52617600,638668800,
%T 8382528000,118313395200,1787154969600,28768836096000,491685562368000,
%U 8892185702400000,169662903201792000,3406062811447296000,71770609241210880000,1583819207322992640000
%N a(n) = n!*(3*n-1)/2.
%H Harry J. Smith, <a href="/A066118/b066118.txt">Table of n, a(n) for n=1..100</a>
%F E.g.f.: (1+x/2)/(1-x)^2. - _Len Smiley_, Dec 06 2001
%F 3*a(n) +(-3*n-7)*a(n-1) +4*(n-1)*a(n-2)=0. - _R. J. Mathar_, Oct 30 2015
%F (-3*n+4)*a(n) +n*(3*n-1)*a(n-1)=0. - _R. J. Mathar_, Oct 30 2015
%F a(n) = A001563(n) + A001286(n). - _Anton Zakharov_, Oct 17 2016
%t Array[#!*(3*#-1)/2 &, 25] (* _Paolo Xausa_, Feb 16 2024 *)
%o (PARI) { for (n=1, 100, write("b066118.txt", n, " ", (n!*(3*n - 1))/2) ) } \\ _Harry J. Smith_, Feb 01 2010
%K nonn,easy
%O 1,2
%A _George E. Antoniou_, Dec 05 2001
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