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A058580 a(n) is the least natural number m such that the fractional part of m*(2^0.5) is less than 2^(-n). 1
1, 3, 5, 17, 29, 29, 99, 169, 577, 985, 985, 3363, 5741, 19601, 33461, 33461, 114243, 195025, 195025, 1136689, 1136689 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Since 2^0.5 is irrational such m must exist because for any irrational number a the sequence a,2a,3a,4a,5a,... is dense modulo 1.

All terms are contained in A079496. - Ralf Stephan, Sep 09 2004

LINKS

Table of n, a(n) for n=1..21.

FORMULA

a(n) = min m such that m*(2^0.5)-floor(m*(2^0.5)) < 2^(-n)

EXAMPLE

a(7) = 99 because 99*(2^0.5) = 140.00714267... and 0.00714267... < 2^(-7) = 0.0078125 and 99 is the least natural number that satisfies this inequality.

PROG

(PARI) o=1:for(n=1, 50, for(m=o, 10^9, if(frac(sqrt(2)*m)<2^(-n), print1(m", "):o=m:break)))

CROSSREFS

Sequence in context: A193066 A193070 A030077 * A161682 A079373 A181291

Adjacent sequences:  A058577 A058578 A058579 * A058581 A058582 A058583

KEYWORD

nonn

AUTHOR

Avi Peretz (njk(AT)netvision.net.il), Dec 25 2000

EXTENSIONS

More terms from Ralf Stephan, Mar 27 2003

STATUS

approved

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Last modified July 23 12:06 EDT 2021. Contains 346259 sequences. (Running on oeis4.)