A242620 a(n) is the largest number in the interval (1, 2^(2^(n-1))) that is a member of a pair of integers the sum of whose squares is equal to the Fermat number 2^(2^n) + 1, or 0 if no such number exists.

0, 0, 0, 0, 0, 62264, 4046803256, 16382350221535464479, 339840244399005511779394711120340266111

Offset

0,6

Comments

2^(2^n) + 1 belongs to A019434 if and only if a(n) = 0.

Links

Table of n, a(n) for n=0..8.

Wikipedia, Fermat number

Crossrefs

Cf. A000215, A242619.

Sequence in context: A083488 A360838 A181114 * A203046 A180163 A180202

Adjacent sequences: A242617 A242618 A242619 * A242621 A242622 A242623

Keyword

nonn

Author

Arkadiusz Wesolowski, May 19 2014

Status

approved