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A091835
Double factorial of primes.
1
2, 3, 15, 105, 10395, 135135, 34459425, 654729075, 316234143225, 6190283353629375, 191898783962510625, 8200794532637891559375, 13113070457687988603440625, 563862029680583509947946875, 1192568192774434123539907640625, 157952079428395476360490147277859375
OFFSET
1,1
LINKS
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
Sequence in context: A238711 A362999 A165657 * A131612 A297421 A180723
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