A085158 Sextuple factorials, 6-factorials, n!!!!!!, n!6.
1, 1, 2, 3, 4, 5, 6, 7, 16, 27, 40, 55, 72, 91, 224, 405, 640, 935, 1296, 1729, 4480, 8505, 14080, 21505, 31104, 43225, 116480, 229635, 394240, 623645, 933120, 1339975, 3727360, 7577955, 13404160, 21827575, 33592320, 49579075, 141639680
Offset: 0
Keywords
Examples
a(14) = 224 because 14*a(14-6) = 14*a(8) = 14*16 = 224.
Links
- G. C. Greubel, Table of n, a(n) for n = 0..1000
- Eric Weisstein's World of Mathematics, Multifactorial.
Crossrefs
Programs
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GAP
a:= function(n) if n<1 then return 1; else return n*a(n-6); fi; end; List([0..40], n-> a(n) ); # G. C. Greubel, Aug 21 2019 -
Magma
b:=func< n | n le 6 select n else n*Self(n-6) >; [1] cat [b(n): n in [1..40]]; // G. C. Greubel, Aug 21 2019
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Maple
a:= n-> `if`(n<1, 1, n*a(n-6)); seq(a(n), n=0..40); # G. C. Greubel, Aug 21 2019
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Mathematica
Table[Times@@Range[n,1,-6],{n,0,40}] (* Harvey P. Dale, Aug 10 2019 *) -
PARI
a(n)=if(n<1, 1, n*a(n-6)); vector(40, n, n--; a(n) ) \\ G. C. Greubel, Aug 21 2019
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Sage
def a(n): if (n<1): return 1 else: return n*a(n-6) [a(n) for n in (0..40)] # G. C. Greubel, Aug 21 2019
Formula
a(n)=1 for n < 1, otherwise a(n) = n*a(n-6).
Sum_{n>=0} 1/a(n) = A288093. - Amiram Eldar, Nov 10 2020
Comments