A242619 - cp's OEIS frontend

A242619 a(n) is the smallest 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.

%I A242619 #10 May 21 2014 20:57:29
%S A242619 0,0,0,0,0,20449,1438793759,8479443857936402504,
%T A242619 17340632172455487023654788790090010704
%N A242619 a(n) is the smallest 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.
%C A242619 2^(2^n) + 1 belongs to A019434 if and only if a(n) = 0.
%H A242619 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fermat_number">Fermat number</a>
%Y A242619 Cf. A000215, A242620.
%K A242619 nonn
%O A242619 0,6
%A A242619 _Arkadiusz Wesolowski_, May 19 2014

cp's OEIS Frontend

A242619 a(n) is the smallest 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.