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A122165 Continued fraction expansion of constant x = Sum_{n>=0} 1/5^(2^n). 1
0, 4, 7, 5, 5, 3, 5, 7, 5, 3, 7, 5, 3, 5, 5, 7, 5, 3, 7, 5, 5, 3, 5, 7, 3, 5, 7, 5, 3, 5, 5, 7, 5, 3, 7, 5, 5, 3, 5, 7, 5, 3, 7, 5, 3, 5, 5, 7, 3, 5, 7, 5, 5, 3, 5, 7, 3, 5, 7, 5, 3, 5, 5, 7, 5, 3, 7, 5, 5, 3, 5, 7, 5, 3, 7, 5, 3, 5, 5, 7, 5, 3, 7, 5, 5, 3, 5, 7, 3, 5, 7, 5, 3, 5, 5, 7, 3, 5, 7, 5, 5, 3, 5, 7, 5 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Consists entirely of 3's, 5's and 7's, after an initial partial quotient of 4. These partial quotients are aperiodic.

EXAMPLE

x=[0;4,7,5,5,3,5,7,5,3,7,5,3,5,5,7,5,3,7,5,5,3,5,7,3,5,7,5,3,5,5,7,5,...].

x=0.2416025600065536000000429496729600000000000018446744073709551616000...

Decimal expansion (A078886) consists of large gaps of zeros between strings of digits that form powers of 2; this can be seen by grouping the digits as follows:

x = .2 4 16 0 256 000 65536 000000 4294967296 000000000000 ...

and then recognizing the substrings as powers of 2:

2 = 2^(2^0), 4 = 2^(2^1), 16 = 2^(2^2), 65536 = 2^(2^4),

4294967296 = 2^(2^5), 18446744073709551616 = 2^(2^6), ...

PROG

(PARI) {a(n)=local(x=sum(k=0, ceil(3+log(n+1)), 1/5^(2^k))); contfrac(x)[n+1]}

CROSSREFS

Cf. A078886.

Sequence in context: A175348 A079356 A146539 * A086202 A107824 A085674

Adjacent sequences:  A122162 A122163 A122164 * A122166 A122167 A122168

KEYWORD

cofr,nonn

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), Aug 22 2006

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Last modified February 17 03:37 EST 2012. Contains 205978 sequences.