A288327 Decuple factorial, 10-factorial, n!10, n!!!!!!!!!!.
1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 24, 39, 56, 75, 96, 119, 144, 171, 200, 231, 528, 897, 1344, 1875, 2496, 3213, 4032, 4959, 6000, 7161, 16896, 29601, 45696, 65625, 89856, 118881, 153216, 193401, 240000, 293601, 709632, 1272843, 2010624, 2953125, 4133376
Offset: 0
Examples
a(13) = 13 * 3 * 1 = 39.
Links
- Robert Price, Table of n, a(n) for n = 0..803
- Eric Weisstein's World of Mathematics, Multifactorial.
Programs
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GAP
a:= function(n) if n<1 then return 1; else return n*a(n-10); fi; end; List([0..50], n-> a(n) ); # G. C. Greubel, Aug 22 2019 -
Magma
b:=func< n | n le 10 select n else n*Self(n-10) >; [1] cat [b(n): n in [1..50]]; // G. C. Greubel, Aug 22 2019
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Maple
a:= n-> `if`(n<1, 1, n*a(n-10)); seq(a(n), n=0..50); # G. C. Greubel, Aug 22 2019
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Mathematica
MultiFactorial[n_, k_]:=If[n<1, 1 ,n*MultiFactorial[n-k, k]]; Table[MultiFactorial[i, 10], {i, 0, 100}] Table[Times@@Range[n,1,-10],{n,0,50}] (* Harvey P. Dale, Aug 11 2019 *) -
PARI
a(n)=if(n<1, 1, n*a(n-10)); vector(40, n, n--; a(n) ) \\ G. C. Greubel, Aug 22 2019
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Sage
def a(n): if (n<1): return 1 else: return n*a(n-10) [a(n) for n in (0..50)] # G. C. Greubel, Aug 22 2019
Formula
a(n)=1 for n < 1, otherwise a(n) = n*a(n-10).
Sum_{n>=0} 1/a(n) = A342033. - Amiram Eldar, May 23 2022