A125599 Quotient ((2n)^(2n-2)-1)/(2n+1)/(2n-1).

0, 1, 37, 4161, 1010101, 432988561, 290738012181, 282578800148737, 375973780484811925, 657002506265664160401, 1460516560427337565647925, 4026980002567282984447709761, 13491386325240318454518243016437

Offset

1,3

Links

Table of n, a(n) for n=1..13.

Formula

a(n) = A125598[2n-1]/(2n+1). a(n) = (A000272[2n]-1)/(2n+1)/(2n-1). a(n) = (b^(n-1)-1)/(b-1), for b = (2n)^2.

Mathematica

Table[(((2n)^(n-1))^2-1)/(2n+1)/(2n-1), {n, 1, 20}]

Crossrefs

Cf. A125598 = ((n+1)^(n-1)-1)/n. Cf. A000272 = n^(n-2).

Sequence in context: A334259 A139043 A305142 * A219409 A232302 A363871

Adjacent sequences: A125596 A125597 A125598 * A125600 A125601 A125602

Keyword

nonn

Author

Alexander Adamchuk, Nov 26 2006

Status

approved