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%I #45 Sep 05 2022 12:42:38
%S 2,5,11,17,19,29,37,41,53,67,71,83,89,101,103,107,109,127,131,149,151,
%T 173,179,181,197,199,227,229,233,239,257,263,269,271,293,331,337,367,
%U 373,379,401,409,419,443,449,457,461,487,491,499,503,541,547,577,587,593,599
%N Primes p for which the continued fraction expansion of sqrt(p) does not have a 1 in the second position.
%C These are the primes that are located between a square number and its following oblong number. - _Charles Kusniec_, Apr 17 2020
%C Primes in A063656. - _Charles Kusniec_, Sep 04 2022
%H Michel Marcus, <a href="/A307508/b307508.txt">Table of n, a(n) for n = 1..5000</a>
%H Piotr Miska and Maciej Ulas, <a href="https://doi.org/10.1080/10586458.2019.1605319">On consecutive 1's in continued fractions expansions of square roots of prime numbers</a>, Experimental Mathematics, 31:1 (2022), 238-251. Also <a href="https://arxiv.org/abs/1904.03404">arXiv:1904.03404</a> [math.NT], 2019.
%H <a href="/index/Con#confC">Index entries for continued fractions for constants</a>
%e For p = 2, we have [1; 2, ...]; see A040000.
%e For p = 5, we have [2; 4, ...]; see A040002.
%e For p = 11, we have [3; 3, ...]; see A040007.
%o (PARI) isok(p) = isprime(p) && contfrac(sqrt(p))[2] != 1;
%Y Cf. A040000, A040002, A040007, A067614, A307453, A063656.
%Y Complement of A334163 with respect to the primes.
%K nonn
%O 1,1
%A _Michel Marcus_, Apr 11 2019
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