A137643 a(n) = ((2n)^((2n+1)^2) + 1)/(2n+1)^3.

1, 19, 9007199254741, 392750863685502459010271914701912679, 19389268200585836264288587113776883575610248525384021488302948711030121, 7513148009015777610818933132982719759579263711495116453794139744552967693463561232156273478587528174305033809166040571

Offset

0,2

Links

Table of n, a(n) for n=0..5.

Formula

a(n) = ((2n)^((2n+1)^2) + 1)/(2n+1)^3.

Mathematica

Table[ ((2n)^((2n+1)^2) + 1)/(2n+1)^3, {n, 0, 10} ]

Crossrefs

Cf. A137641 (((n-1)^(n^2) + 1)/n^3).

Cf. A137642 (((p+1)^(p^2) - 1)/p^3 where p = prime(n)).

Cf. A133591 (((p-1)^(p^2) + 1)/p^3 where p = prime(n)).

Sequence in context: A128400 A211378 A133591 * A351570 A023921 A072840

Adjacent sequences: A137640 A137641 A137642 * A137644 A137645 A137646

Keyword

nonn

Author

Alexander Adamchuk, Jan 31 2008

Status

approved