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A334163
Primes p whose continued fraction expansion of sqrt(p) has a 1 in the second position.
2
3, 7, 13, 23, 31, 43, 47, 59, 61, 73, 79, 97, 113, 137, 139, 157, 163, 167, 191, 193, 211, 223, 241, 251, 277, 281, 283, 307, 311, 313, 317, 347, 349, 353, 359, 383, 389, 397, 421, 431, 433, 439, 463, 467, 479, 509, 521, 523, 557, 563, 569, 571, 601, 607, 613, 617, 619
OFFSET
1,1
COMMENTS
These are the primes that are located between an oblong number and its following square number. - Charles Kusniec, Apr 17 2020
Primes in A063657. - Charles Kusniec, Sep 04 2022
LINKS
MAPLE
3, seq(op(select(isprime, [$(t^2+t+1)..(t^2+2*t-1)])), t=1..31); # Robert Israel, Apr 20 2020
MATHEMATICA
Select[Range[1000], PrimeQ[#] && ContinuedFraction[Sqrt[#]][[2, 1]] == 1 &] (* Amiram Eldar, Apr 17 2020 *)
Select[Prime[Range[150]], ContinuedFraction[Sqrt[#]][[2, 1]]==1&] (* Harvey P. Dale, Mar 04 2022 *)
PROG
(PARI) isok(p) = isprime(p) && contfrac(sqrt(p))[2] == 1;
CROSSREFS
Complement of A307508 with respect to the primes.
Cf. A063657.
Sequence in context: A081662 A091652 A372209 * A291546 A134197 A053001
KEYWORD
nonn
AUTHOR
Michel Marcus, Apr 17 2020
STATUS
approved