The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS"). Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A034177 a(n) = n-th quartic factorial number divided by 4. 17
 1, 8, 96, 1536, 30720, 737280, 20643840, 660602880, 23781703680, 951268147200, 41855798476800, 2009078326886400, 104472072998092800, 5850436087893196800, 351026165273591808000, 22465674577509875712000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Michael De Vlieger, Table of n, a(n) for n = 1..365 INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 513 Norihiro Nakashima, Shuhei Tsujie, Enumeration of Flats of the Extended Catalan and Shi Arrangements with Species, arXiv:1904.09748 [math.CO], 2019. FORMULA 4*a(n) = (4*n)(!^4) = product_{j=1..n} 4*j = 4^n * n!. E.g.f.: (-1 + 1/(1-4*x))/4. D-finite with recurrence: a(n) -4*n*a(n-1)=0. - R. J. Mathar, Feb 24 2020 EXAMPLE G.f. = x + 8*x^2 + 96*x^3 + 1536*x^4 + 30720*x^5 + 737820*x^6 + ... MAPLE [seq(n!*4^(n-1), n=1..16)]; # Zerinvary Lajos, Sep 23 2006 MATHEMATICA Array[4^(# - 1) #! &, 16] (* Michael De Vlieger, May 30 2019 *) PROG (PARI) vector(20, n, 4^(n-1)*n!) \\ G. C. Greubel, Aug 15 2019 (MAGMA) [4^(n-1)*Factorial(n): n in [1..20]]; // G. C. Greubel, Aug 15 2019 (Sage) [4^(n-1)*factorial(n) for n in (1..20)] # G. C. Greubel, Aug 15 2019 (GAP) List([1..20], n-> 4^(n-1)*Factorial(n) ); # G. C. Greubel, Aug 15 2019 CROSSREFS Cf. A007696, A000407, A034176. First column of triangle A048786. A052570 is an essentially identical sequence. - Philippe Deléham, Sep 18 2008 Equals the second right hand column of A167569 divided by 2. - Johannes W. Meijer, Nov 12 2009 Sequence in context: A260627 A098430 A220285 * A052570 A002168 A114425 Adjacent sequences:  A034174 A034175 A034176 * A034178 A034179 A034180 KEYWORD easy,nonn AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 28 12:15 EST 2020. Contains 338720 sequences. (Running on oeis4.)