A001805 a(n) = n! * binomial(n,3).
6, 96, 1200, 14400, 176400, 2257920, 30481920, 435456000, 6586272000, 105380352000, 1780927948800, 31732897996800, 594991837440000, 11716762337280000, 241867451105280000, 5224336943874048000, 117874102296158208000, 2773508289321369600000
Offset: 3
Keywords
References
- M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 799.
- N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Links
- T. D. Noe, Table of n, a(n) for n = 3..100
- M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
- Index entries for sequences related to Laguerre polynomials
Crossrefs
Essentially a column of triangle A021012.
Programs
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Magma
[Factorial(n)*Binomial(n,3): n in [3..30]]; // G. C. Greubel, May 17 2018
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Maple
G(x):=x^3/(1-x)^4: f[0]:=G(x): for n from 1 to 18 do f[n]:=diff(f[n-1],x) od: x:=0: seq(f[n],n=3..18); # Zerinvary Lajos, Apr 01 2009
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Mathematica
Table[n! Binomial[n,3], {n,3,30}] (* Harvey P. Dale, Feb 23 2011 *)
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PARI
for(n=3, 30, print1(n!*binomial(n,3), ", ")) \\ G. C. Greubel, May 17 2018
Formula
E.g.f.: x^3/(1-x)^4. - Geoffrey Critzer, Aug 19 2012
Extensions
More terms from Ralf Stephan, Jan 09 2004
Comments