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A086397
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Numerators of the rational convergents to sqrt(2) if both numerators and denominators are primes.
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3
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OFFSET
| 1,1
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COMMENTS
| Next term, if it exists, is bigger than 489 digits (the 1279th convergent to sqrt(2)). - Joshua Zucker (joshua.zucker(AT)stanfordalumni.org), May 08 2006
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MATHEMATICA
| For[n = 2, n < 1500, n++, a := Join[{1}, Table[2, {i, 2, n}]]; If[PrimeQ[Denominator[FromContinuedFraction[a]]], If[PrimeQ[Numerator[FromContinuedFraction[a]]], Print[Numerator[FromContinuedFraction[a]]]]]] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), May 09 2006
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PROG
| (PARI) cfracnumdenomprime(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)&&ispseudoprime(denom), print1(numer", "); numer2=numer; denom2=denom); ) default(realprecision, 28); }
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CROSSREFS
| Sequence in context: A181148 A179907 A080581 * A019018 A018993 A160615
Adjacent sequences: A086394 A086395 A086396 * A086398 A086399 A086400
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KEYWORD
| frac,more,nonn
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AUTHOR
| Cino Hilliard (hillcino368(AT)gmail.com), Sep 06 2003
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EXTENSIONS
| More terms from Cino Hilliard (hillcino368(AT)gmail.com), Jan 15 2005
Edited by N. J. A. Sloane, Aug 06 2009 at the suggestion of R. J. Mathar
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