A338167 -id:A338167 - cp's OEIS frontend

A085535 a(n) = (2n)^(2n-1).

2, 64, 7776, 2097152, 1000000000, 743008370688, 793714773254144, 1152921504606846976, 2185911559738696531968, 5242880000000000000000000, 15519448971100888972574851072, 55572324035428505185378394701824, 236773830007967588876795164938469376

Offset: 1

N. J. A. Sloane, Jul 05 2003

nonn

a(0) is 0^(-1) = 1/0, which is undefined.

Cf. A005408, A005843, A222621, A338167.

Table[(2*n)^(2*n - 1), {n, 20}] (* T. D. Noe, Feb 26 2013 *)

a(n) = A005843(n)^A005408(n-1). - Michel Marcus, Apr 14 2018

Sum_{n>=1} 1/a(n) = A338167. - Amiram Eldar, Nov 29 2020

A338168 Decimal expansion of Sum_{n>=1} 1/(2n-1)^(2n).

Original entry on oeis.org

1, 0, 1, 2, 4, 0, 9, 8, 5, 2, 7, 6, 5, 9, 8, 7, 3, 2, 0, 4, 6, 8, 1, 8, 5, 7, 2, 7, 0, 1, 9, 3, 5, 4, 8, 7, 7, 0, 7, 1, 7, 2, 6, 4, 3, 0, 7, 0, 7, 0, 7, 8, 9, 1, 7, 3, 0, 0, 9, 1, 0, 5, 6, 0, 5, 0, 0, 2, 2, 6, 6, 7, 8, 8, 0, 2, 3, 0, 6, 6, 7, 1, 2, 1, 2, 1, 9, 1

Offset: 1

Mario Cortés, Oct 14 2020

This is the sum of the inverse of odd numbers raised to the even numbers.

			1.0124098527659873204681857270193548770717264307070789173009...

Cf. A073009, A222621, A338167.

PARI
```
suminf(n=1, (2*n-1)^(-2*n))
```

Equals Sum_{n>=1} 1/A222621(n).

cp's OEIS Frontend

A085535 a(n) = (2n)^(2n-1).

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