A221521 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A221521 as a simple table

`n`		`a(n)`
`1`		`0`
`2`		`20`
`3`		`68`
`4`		`400`
`5`		`1940`
`6`		`9982`
`7`		`50400`
`8`		`256018`
`9`		`1297924`
`10`		`6584320`
`11`		`33394958`
`12`		`169387004`
`13`		`859152000`
`14`		`4357755890`
`15`		`22103183110`
`16`		`112110699524`
`17`		`568642349004`
`18`		`2884239836106`
`19`		`14629299498936`
`20`		`74202014273586`
`21`		`376363810775194`

[0,20,68,400,1940,9982,50400,256018,1297924, 6584320,33394958,169387004,859152000,4357755890, 22103183110,112110699524,568642349004, 2884239836106,14629299498936,74202014273586, 376363810775194]

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 23 08:33 EDT 2024. Contains 371905 sequences. (Running on oeis4.)