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A086386 Numerators of the rational convergents to sqrt(3) if both numerators and denominators are primes. 5
5, 19, 71, 3691, 191861, 26947261171 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

These numbers are rare.

LINKS

Table of n, a(n) for n=1..6.

PROG

(PARI) cfracnum(m, f) = { cfr = vector(10000); x=f; for(n=0, m, i=floor(x); x=1/(x-i); cfr[n+1] = i; ); for(m1=0, m, r=cfr[m1+1]; forstep(n=m1, 1, -1, r = 1/r; r+=cfr[n]; ); numer=numerator(r); denom=denominator(r); if(isprime(numer) & isprime(denom), print1(numer", ")); ) }

CROSSREFS

Cf. A001834.

Sequence in context: A149761 A149762 A299107 * A289925 A047155 A295046

Adjacent sequences:  A086383 A086384 A086385 * A086387 A086388 A086389

KEYWORD

nonn,frac,more

AUTHOR

Cino Hilliard, Sep 06 2003

STATUS

approved

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Last modified April 25 00:29 EDT 2019. Contains 322446 sequences. (Running on oeis4.)