A307031 n to the power n double factorial, n^(n!!).

1, 4, 27, 65536, 30517578125, 22452257707354557240087211123792674816, 54361846697263307560529495055267343940077014163990039113495978834700158362117849904436807

Offset

1,2

Comments

The next term -- a(8) -- has 347 digits. - Harvey P. Dale, Aug 11 2021

Links

Table of n, a(n) for n=1..7.

Eric Weisstein's World of Mathematics, Double Factorial

Formula

a(n) = n^(n!!).

Mathematica

Table[n^n!!, {n, 7}] (* Harvey P. Dale, Aug 11 2021 *)

Prog

(Python)
def doublefactorial(n):
     if n <= 0:
         return 1
     else:
         return n * doublefactorial(n-2)
for n in range(1, m):
    print(n**doublefactorial(n))

Crossrefs

Cf. A254866, A053986.

Sequence in context: A292968 A000869 A132640 * A306823 A174212 A352838

Adjacent sequences: A307028 A307029 A307030 * A307032 A307033 A307034

Keyword

nonn

Author

Mark Stander, Mar 20 2019

Status

approved