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

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

Offset: 1

Author

Mark Stander, Mar 20 2019

Keywords

• nonn

Comments

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

Links

• Eric Weisstein's World of Mathematics, Double Factorial

Crossrefs

Cf. A254866, A053986.

Programs

Mathematica

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

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))

Formula

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