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A307508 Primes p for which the continued fraction expansion of sqrt(p) does not have a 1 in the second position. 0
2, 5, 11, 17, 19, 29, 37, 41, 53, 67, 71, 83, 89, 101, 103, 107, 109, 127, 131, 149, 151, 173, 179, 181, 197, 199, 227, 229, 233, 239, 257, 263, 269, 271, 293, 331, 337, 367, 373, 379, 401, 409, 419, 443, 449, 457, 461, 487, 491, 499, 503, 541, 547, 577, 587, 593, 599 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..57.

Piotr Miska, Maciej Ulas, On consecutive 1's in continued fractions expansions of square roots of prime numbers, arXiv:1904.03404 [math.NT], 2019.

Index entries for continued fractions for constants

EXAMPLE

For p = 2,  we have [1; 2, ...]; see A040000.

For p = 5,  we have [2; 4, ...]; see A040002.

For p = 11, we have [3; 3, ...]; see A040007.

PROG

(PARI) isok(p) = isprime(p) && contfrac(sqrt(p))[2] != 1;

CROSSREFS

Cf. A040000, A040002, A040007, A307453

Sequence in context: A080165 A239712 A224363 * A063535 A091653 A088348

Adjacent sequences:  A307505 A307506 A307507 * A307509 A307510 A307511

KEYWORD

nonn

AUTHOR

Michel Marcus, Apr 11 2019

STATUS

approved

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Last modified September 20 16:30 EDT 2019. Contains 327242 sequences. (Running on oeis4.)