OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..140
FORMULA
a(n) = prime(n)!!.
EXAMPLE
a(2) = 3 because 3*1 = 3;
a(3) = 15 because 5*3*1 = 15;
......
MAPLE
a:= n-> doublefactorial(ithprime(n)):
seq(a(n), n=1..20); # Alois P. Heinz, Jul 24 2017
MATHEMATICA
Table[ Prime[n]!!, {n, 14}]
PROG
(Magma) DoubleFactorial:=func< n | &*[n..2 by -2] >; [ DoubleFactorial(NthPrime(n)): n in [1..16] ]; // Vincenzo Librandi, Jul 24 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Mar 09 2004
EXTENSIONS
More terms from Robert G. Wilson v, Mar 11 2004
STATUS
approved