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User: Mark Stander

Mark Stander has authored 2 sequences.

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

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

Offset: 1

Mark Stander, Mar 20 2019

nonn

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

Eric Weisstein's World of Mathematics, Double Factorial

Cf. A254866, A053986.

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

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

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

A322184 List of primes that appear in the 3 X 3 matrices A, B, C which are the smallest solution to the matrix equation AB = C in square matrices composed of distinct primes.

Original entry on oeis.org

3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 1549, 1553, 1619, 1741, 1759, 2053, 2083, 2129, 2437

Offset: 1

Mark Stander, Nov 30 2018

Found using computation. The solution is smallest by total sum.

			Solution to AB = C:
A = {{3, 29, 19}, {7, 17, 11}, {5, 13, 23}};
B = {{67, 61, 59}, {37, 43, 47}, {41, 53, 31}};
C = {{2053, 2437, 2129}, {1549, 1741, 1553}, {1759, 2083, 1619}}.

Mark Stander, The Smallest Solution to AB = C, Where A, B, and C are Square Matrices Composed of Distinct Primes, The American Mathematical Monthly, 125 (2018), 754-754.

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User: Mark Stander

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

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