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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 (list; graph; refs; listen; history; text; internal format)
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

Cf. A001147, A006882.

Sequence in context: A107413 A238711 A165657 * A131612 A297421 A180723

Adjacent sequences:  A091832 A091833 A091834 * A091836 A091837 A091838

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

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Last modified May 21 01:01 EDT 2019. Contains 323429 sequences. (Running on oeis4.)