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A086791 Primes found among the numerators of the continued fraction rational approximations to e. 1
2, 3, 11, 19, 193, 49171, 1084483, 563501581931, 332993721039856822081, 3883282200001578119609988529770479452142437123001916048102414513139044082579 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

LINKS

Cino Hilliard, Continued fractions rational approximation of numeric constants.

EXAMPLE

The first 8 rational approximations to e are 2/1, 3/1, 8/3, 11/4, 19/7, 87/32, 106/39, 193/71. The numerators 2, 3, 11, 19, 193 are primes.

PROG

(PARI) \Continued fraction rational approximation of numeric constants f. m=steps. cfracnumprime(m, f) = { default(realprecision, 3000); cf = vector(m+10); x=f; for(n=0, m, i=floor(x); x=1/(x-i); cf[n+1] = i; ); for(m1=0, m, r=cf[m1+1]; forstep(n=m1, 1, -1, r = 1/r; r+=cf[n]; ); numer=numerator(r); denom=denominator(r); if(ispseudoprime(numer), print1(numer, ", ")); ) }

CROSSREFS

Cf. A086788.

Sequence in context: A051097 A076201 A129668 * A004687 A097895 A023182

Adjacent sequences:  A086788 A086789 A086790 * A086792 A086793 A086794

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard (hillcino368(AT)gmail.com), Aug 04 2003; corrected Jul 24 2004

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Last modified February 16 21:17 EST 2012. Contains 205971 sequences.