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A101411 Denominator when the numerator of the continued fraction rational approximation of sqrt(2) is prime. Also the denominators of A086395(n). 2
2, 5, 12, 29, 169, 408, 470832, 6625109, 44560482149, 345869461223138161, 13558774610046711780701, 87275373599917999482560755526644279276078854297832438763690789 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..12.

PROG

(PARI) cfracnum(m, f) = { local(x, r, cfr, i, m1); default(realprecision, 3000); numer2=0; denom2=0; cfr = vector(m+100); 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(ispseudoprime(numer), print1(denom", ")); ); default(realprecision, 28);

CROSSREFS

Cf. A086395.

Sequence in context: A261234 A324787 A228516 * A042789 A291253 A101911

Adjacent sequences:  A101408 A101409 A101410 * A101412 A101413 A101414

KEYWORD

frac,nonn

AUTHOR

Cino Hilliard, Jan 15 2005

STATUS

approved

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Last modified January 27 12:01 EST 2020. Contains 331295 sequences. (Running on oeis4.)