|
| |
|
|
A114800
|
|
Octuple factorial, 8-factorial, n!8, n!!!!!!!!.
|
|
15
|
|
|
|
1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 20, 33, 48, 65, 84, 105, 128, 153, 360, 627, 960, 1365, 1848, 2415, 3072, 3825, 9360, 16929, 26880, 39585, 55440, 74865, 98304, 126225, 318240, 592515, 967680, 1464645, 2106720, 2919735, 3932160, 5175225, 13366080
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,3
|
|
|
LINKS
|
|
|
|
FORMULA
|
a(n) = 1 for n<1, else a(n) = n*a(n-8).
|
|
|
EXAMPLE
|
a(10) = 10 * a(10-8) = 10 * a(2) = 10 * 2 = 20.
a(20) = 20 * a(20-8) = 20 * a(12) = 20 * (12*a(12-8)) = 20 * 12 * a(4) = 20 * 12 * 4 = 960.
a(30) = 30 * a(30-8) = 30 * a(22) = 30 * (22*a(22-8)) = 30 * 22 * a(14) = 30 * 22 * (14*a(14-8)) = 30 * 22 * 14 * 6 = 55440.
|
|
|
MAPLE
|
option remember;
if n < 1 then
1;
else
n*procname(n-8) ;
end if;
end proc:
|
|
|
MATHEMATICA
|
Table[Times@@Range[n, 1, -8], {n, 0, 50}] (* Harvey P. Dale, Feb 17 2018 *)
|
|
|
PROG
|
(PARI) a(n)=if(n<1, 1, n*a(n-8));
(Magma) b:=func< n | n le 8 select n else n*Self(n-8) >;
(Sage)
def a(n):
if (n<1): return 1
else: return n*a(n-8)
(GAP)
a:= function(n)
if n<1 then return 1;
else return n*a(n-8);
fi;
end;
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
easy,nonn
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
