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A128848 Numerators of the continued fraction convergents of the decimal concatenation of the twin prime pairs. 0
0, 1, 1, 5, 16, 37, 53, 355, 1118, 3709, 8536, 12245, 204456, 421157, 1467927, 1889084, 5246095, 7135179, 12381274, 93804097, 106185371, 306174839, 412360210, 718535049, 1130895259, 2980325567, 16032523094, 35045371755 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..27.

FORMULA

The twin prime pairs 3,5,5,7,11,13,17,19... are concatenated and then preceded by a decimal point to create the fraction N = .3557111317192931... 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) cattwinP(n) = { a="."; forprime(x=3, n, if(ispseudoprime(x+2), a=concat(a, Str(x)); a=concat(a, Str(x+2)))); 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(numer", "); ) }

CROSSREFS

Sequence in context: A211806 A001210 A264552 * A274248 A188427 A022496

Adjacent sequences:  A128845 A128846 A128847 * A128849 A128850 A128851

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 March 30 12:10 EDT 2020. Contains 333125 sequences. (Running on oeis4.)