A338168 -id:A338168 - cp's OEIS frontend

A222621 a(n) = (2n-1)^(2n).

1, 81, 15625, 5764801, 3486784401, 3138428376721, 3937376385699289, 6568408355712890625, 14063084452067724991009, 37589973457545958193355601, 122694327386105632949003612841, 480250763996501976790165756943041, 2220446049250313080847263336181640625

Offset: 1

Dave Durgin, Feb 26 2013

			1^2; 3^4; 5^6; 7^8 and so on.

Vincenzo Librandi, Table of n, a(n) for n = 1..190

Cf. A005408, A005843, A085535, A338168.

[(2*n - 1)^(2*n): n in [1..13]]; // Vincenzo Librandi, Feb 26 2013

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

a(n)=(2*n-1)^(2*n) \\ Charles R Greathouse IV, Aug 20 2013

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

Sum_{n>=1} 1/a(n) = A338168. - Amiram Eldar, Nov 29 2020

A338167 Decimal expansion of Sum_{n>=1} 1/(2n)^(2n-1).

Original entry on oeis.org

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

Offset: 0

Mario Cortés, Oct 14 2020

Is the sum of the inverse of even numbers raised to the odd numbers.

			0.51575407866155061123838088838465692424297596755674236022...

Cf. A085535, A338168.

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

Equals Sum_{n>=1} 1/A085535(n).

More terms from Jon E. Schoenfield, Mar 21 2021

cp's OEIS Frontend

A222621 a(n) = (2n-1)^(2n).

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