%I #18 Feb 25 2015 05:25:39

%S 1,2,2,3,3,4,4,4,5,6,5,5,7,6,6,7,7,9,7,7,8,10,8,9,8,8,9,11,10,9,10,13,

%T 11,10,13,14,12,11,13,11,11,12,13,12,14,13,16,12,12,17,13,14,13,16,13,

%U 18,14,16,15,14,17,14,15,14,14,14,17,16,19,16,17,16,20

%N One half of the fundamental positive solution y = y1(n) of the first class of the Pell equation x^2 - 2*y^2 = -A007522(n), n >= 1 (primes congruent to 7 mod 8).

%C For the corresponding term x1(n) see A254938(n).

%C See A254938 also for the Nagell reference.

%C The least positive y solutions (that is those of the first class) for the primes +1 and -1 (mod 8) together (including prime 2) are given in A255246.

%F A254938(n)^2 - 2*(2*a(n))^2 = -A007522(n) gives the smallest positive (proper) solution of this (generalized) Pell equation.

%e See A254938.

%e n = 3: 1^2 - 2*(2*2)^2 = 1 - 32 = -31 = -A007522(3).

%Y Cf. A007522, A254938, A255233, A255234, A255246, A254935.

%K nonn,easy

%O 1,2

%A _Wolfdieter Lang_, Feb 18 2015

%E More terms from _Colin Barker_, Feb 23 2015