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 A055304 Number of labeled rooted trees with n nodes and 3 leaves. 1
 4, 140, 3000, 54600, 940800, 16087680, 279417600, 4989600000, 92207808000, 1769511744000, 35321737651200, 733823266176000, 15866448998400000, 356873052856320000, 8344427063132160000, 202660737281114112000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 4,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 4..200 FORMULA a(n) = (n!/3!)*Stirling2(n-1, n-3). - Vladeta Jovovic, Jan 28 2004 a(n) = n! * (n-3)*(n-2)*(n-1)*(3*n-8)/144. - Vaclav Kotesovec, Jul 25 2014 E.g.f.: x^4*(2*x+1)/(6*(1-x)^5). - Robert Israel, Jul 25 2014 MAPLE seq(n!*(n-3)*(n-2)*(n-1)*(3*n-8)/144, n=4..100); # Robert Israel, Jul 25 2014 MATHEMATICA Table[n! * (n-3)*(n-2)*(n-1)*(3*n-8)/144, {n, 4, 20}] (* Vaclav Kotesovec, Jul 25 2014 *) PROG (MAGMA) [Factorial(n)*(n-3)*(n-2)*(n-1)*(3*n-8)/144 : n in [4..25]]; // Vincenzo Librandi, Jul 25 2014 CROSSREFS Column 3 of A055302. Sequence in context: A221675 A291450 A093981 * A270065 A002917 A235536 Adjacent sequences:  A055301 A055302 A055303 * A055305 A055306 A055307 KEYWORD nonn AUTHOR Christian G. Bower, May 11 2000 STATUS approved

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Last modified January 23 01:30 EST 2020. Contains 331166 sequences. (Running on oeis4.)