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A128845 Denominators of the continued fraction convergents of the decimal concatenation of the lower bound of twin primes. 0
1, 2, 3, 17, 20, 37, 94, 131, 225, 581, 806, 1387, 2193, 3580, 9353, 12933, 22286, 35219, 57505, 1472844, 1530349, 50444012, 102418373, 255280758, 30480828575, 152659423633, 1251756217639, 1404415641272, 2656171858911, 6716759359094 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..29.

FORMULA

The lower bounds of twin primes 3,5,11,17... are concatenated and then preceded by a decimal point to create the fraction N = .35111729... . 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) cattwinsL(n) = a="."; forprime(x=3, n, if(ispseudoprime(x+2), a=concat(a, Str(x)))); a=eval(a) cfrac2(m, f) = { default(realprecision, 1000); cf = vector(m+10); cf = contfrac(f); for(m1=1, 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", "); ) }

CROSSREFS

Sequence in context: A140834 A121409 A041295 * A128851 A078737 A041981

Adjacent sequences:  A128842 A128843 A128844 * A128846 A128847 A128848

KEYWORD

frac,nonn,base

AUTHOR

Cino Hilliard, Apr 16 2007

EXTENSIONS

Edited by Charles R Greathouse IV, Apr 25 2010

STATUS

approved

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Last modified August 7 15:20 EDT 2020. Contains 336276 sequences. (Running on oeis4.)