A134175
a(n) = (32/2)*(n-1)*(n-2)*(n-3)*(n-4).
Original entry on oeis.org
0, 0, 0, 0, 384, 1920, 5760, 13440, 26880, 48384, 80640, 126720, 190080, 274560, 384384, 524160, 698880, 913920, 1175040, 1488384, 1860480, 2298240, 2808960, 3400320, 4080384, 4857600, 5740800, 6739200, 7862400, 9120384, 10523520, 12082560, 13808640, 15713280
Offset: 1
- G. C. Greubel, Table of n, a(n) for n = 1..1000
- D. Zvonkine, Home Page
- D. Zvonkine, Counting ramified coverings and intersection theory on Hurwitz spaces II (local structure of Hurwitz spaces and combinatorial results), Moscow Mathematical Journal, vol. 7 (2007), no. 1, 135-162.
- Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
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LinearRecurrence[{5, -10, 10, -5, 1}, {0, 0, 0, 0, 384} , 50] (* or *) Table[(32/2)*(n-1)*(n-2)*(n-3)*(n-4), {n,1,50}] (* G. C. Greubel, May 30 2016 *)
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a(n) = 16*(n-1)*(n-2)*(n-3)*(n-4) \\ Michel Marcus, Jun 27 2013
A154128
a(n) = 5^n*(n+4)!/n!.
Original entry on oeis.org
24, 600, 9000, 105000, 1050000, 9450000, 78750000, 618750000, 4640625000, 33515625000, 234609375000, 1599609375000, 10664062500000, 69726562500000, 448242187500000, 2838867187500000, 17742919921875000, 109588623046875000
Offset: 0
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[5^n*(n+4)*(n+3)*(n+2)*(n+1): n in [0..20]]; // Vincenzo Librandi, Aug 15 2011
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LinearRecurrence[{25, -250, 1250, -3125, 3125}, {24, 600, 9000, 105000, 1050000}, 25] (* or *) Table[5^n*(n+4)*(n+3)*(n+2)*(n+1), {n,0,25}] (* G. C. Greubel, Sep 02 2016 *)
A276161
Numbers that are the product of 4 consecutive positive numbers and the product of 2 nontrivial oblong numbers.
Original entry on oeis.org
840, 5040, 11880, 175560, 570024, 5997600, 34234200, 70073640, 569729160, 1262451960, 6643717080, 6927399360, 59312218680, 657557188200, 1288881113520, 7994422608480, 9803968814640, 73148660184600, 130903460103024, 250036769127600, 1081389616791120
Offset: 1
175560 = 19*20*21*22 = 5*6*76*77 = 30*5852.
A277444
Square array A(n,k) (n>=1, k>=1) read by antidiagonals: A(n,k) is the number of n-colorings of the Möbius ladder M_k on 2k vertices.
Original entry on oeis.org
0, 0, 2, 0, 0, 6, 0, 2, 0, 12, 0, 0, 42, 24, 20, 0, 2, 48, 420, 120, 30, 0, 0, 306, 2160, 2420, 360, 42, 0, 2, 600, 17532, 27600, 9750, 840, 56, 0, 0, 2442, 115464, 375260, 191760, 30702, 1680, 72, 0, 2, 6048, 830100, 4810680, 4098510, 917280, 81032, 3024, 90, 0, 0, 20706, 5745120, 62813540, 85691640, 28669662, 3406368, 187560, 5040, 110
Offset: 1
Square array A(n,k) begins:
0, 0, 0, 0, 0, 0, 0, ...
2, 0, 2, 0, 2, 0, 2, ...
6, 0, 42, 48, 306, 600, 2442, ...
12, 24, 420, 2160, 17532, 115464, 830100, ...
20, 120, 2420, 27600, 375260, 4810680, 62813540, ...
30, 360, 9750, 191760, 4098510, 85691640, 1801468230, ...
Cf.
A277443 (colorings of prism graphs),
A182406 (square grid graphs).
A052768
a(n) = n*(n-1)*(n-2)*(n-3) for n>=5.
Original entry on oeis.org
0, 0, 0, 0, 0, 120, 360, 840, 1680, 3024, 5040, 7920, 11880, 17160, 24024, 32760, 43680, 57120, 73440, 93024, 116280, 143640, 175560, 212520, 255024, 303600, 358800, 421200, 491400, 570024, 657720, 755160, 863040, 982080, 1113024
Offset: 0
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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spec := [S,{B=Set(Z,1 <= card),S=Prod(Z,Z,Z,Z,B)},labeled]: seq(combstruct[count](spec,size=n), n=0..20);
More terms and corrected formula from Larry Reeves (larryr(AT)acm.org), Jan 23 2001
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