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A128875 Denominator of the continued fraction convergents of the decimal concatenation of the powers of 2. 0
1, 8, 673, 681, 11569, 12250, 685319, 697569, 1382888, 2080457, 5543802, 13168061, 1546206939, 1559375000, 6224331939, 14008038878, 76264526329, 90272565207, 798445047985, 1687162661177, 66597788833888, 134882740328953 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

FORMULA

The powers of 2 = 1,2,4,8,16,32,64,... are concatenated and then preceded by a decimal point to create the fraction N = .1248163264128... This number is then evaluated with n=0,m=steps to iterate,x = N, a(0)=floor(N) using the loop: do a(n)=floor(x) x=1/(x-a(n)) n=n+1 loop until n=m

PROG

(PARI) g(n) = f="."; for(x=0, n, a=concat(f, 2^x)); f=eval(f) { default(realprecision, 1000); cf = vector(1000); cf = contfrac(f); for(m1=0, m-1, r=cf[m1+1]; forstep(n=m1, 1, -1, r = 1/r; r+=cf[n]; ); numer=numerator(r); denom=denominator(r); print1(denom", "); numer2=numer; denom2=denom; ) }

CROSSREFS

Sequence in context: A099126 A172919 A101180 * A199801 A202910 A168130

Adjacent sequences:  A128872 A128873 A128874 * A128876 A128877 A128878

KEYWORD

frac,nonn,base

AUTHOR

Cino Hilliard (hillcino368(AT)hotmail.com), Apr 18 2007

EXTENSIONS

Edited by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Apr 25 2010

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Last modified February 16 12:41 EST 2012. Contains 205909 sequences.