%I #23 May 23 2022 12:22:36

%S 1,1,2,3,4,5,6,7,8,9,10,11,24,39,56,75,96,119,144,171,200,231,528,897,

%T 1344,1875,2496,3213,4032,4959,6000,7161,16896,29601,45696,65625,

%U 89856,118881,153216,193401,240000,293601,709632,1272843,2010624,2953125,4133376

%N Decuple factorial, 10-factorial, n!10, n!!!!!!!!!!.

%H Robert Price, <a href="/A288327/b288327.txt">Table of n, a(n) for n = 0..803</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Multifactorial.html">Multifactorial</a>.

%F a(n)=1 for n < 1, otherwise a(n) = n*a(n-10).

%F Sum_{n>=0} 1/a(n) = A342033. - _Amiram Eldar_, May 23 2022

%e a(13) = 13 * 3 * 1 = 39.

%p a:= n-> `if`(n<1, 1, n*a(n-10)); seq(a(n), n=0..50); # _G. C. Greubel_, Aug 22 2019

%t MultiFactorial[n_, k_]:=If[n<1, 1 ,n*MultiFactorial[n-k, k]];

%t Table[MultiFactorial[i, 10], {i, 0, 100}]

%t Table[Times@@Range[n,1,-10],{n,0,50}] (* _Harvey P. Dale_, Aug 11 2019 *)

%o (PARI) a(n)=if(n<1, 1, n*a(n-10));

%o vector(40, n, n--; a(n) ) \\ _G. C. Greubel_, Aug 22 2019

%o (Magma) b:=func< n | n le 10 select n else n*Self(n-10) >;

%o [1] cat [b(n): n in [1..50]]; // _G. C. Greubel_, Aug 22 2019

%o (Sage)

%o def a(n):

%o if (n<1): return 1

%o else: return n*a(n-10)

%o [a(n) for n in (0..50)] # _G. C. Greubel_, Aug 22 2019

%o (GAP)

%o a:= function(n)

%o if n<1 then return 1;

%o else return n*a(n-10);

%o fi;

%o end;

%o List([0..50], n-> a(n) ); # _G. C. Greubel_, Aug 22 2019

%Y Cf. A006852, A007661, A007662, A085157, A085158, A114799, A114800, A114806, A342033.

%K easy,nonn

%O 0,3

%A _Robert Price_, Jun 07 2017