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A066118
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a(n) = n!*(3*n-1)/2.
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1
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1, 5, 24, 132, 840, 6120, 50400, 463680, 4717440, 52617600, 638668800, 8382528000, 118313395200, 1787154969600, 28768836096000, 491685562368000, 8892185702400000, 169662903201792000, 3406062811447296000, 71770609241210880000, 1583819207322992640000
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OFFSET
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1,2
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LINKS
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FORMULA
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E.g.f.: (1+x/2)/(1-x)^2. - Len Smiley, Dec 06 2001
3*a(n) +(-3*n-7)*a(n-1) +4*(n-1)*a(n-2)=0. - R. J. Mathar, Oct 30 2015
(-3*n+4)*a(n) +n*(3*n-1)*a(n-1)=0. - R. J. Mathar, Oct 30 2015
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MATHEMATICA
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Array[#!*(3*#-1)/2 &, 25] (* Paolo Xausa, Feb 16 2024 *)
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PROG
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(PARI) { for (n=1, 100, write("b066118.txt", n, " ", (n!*(3*n - 1))/2) ) } \\ Harry J. Smith, Feb 01 2010
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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