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A065444 Decimal expansion of 9*Sum{k=1..inf} 1/(10^k-1). 5
1, 1, 0, 0, 9, 1, 8, 1, 9, 0, 8, 3, 6, 2, 0, 0, 7, 3, 6, 3, 7, 9, 8, 5, 5, 1, 0, 1, 6, 5, 4, 3, 8, 0, 0, 4, 3, 2, 0, 3, 4, 5, 4, 3, 9, 7, 8, 7, 3, 2, 8, 1, 6, 5, 6, 3, 5, 9, 8, 9, 0, 2, 2, 0, 7, 3, 4, 3, 8, 3, 4, 9, 0, 2, 1, 9, 8, 3, 4, 7, 4, 8, 8, 9, 2, 0, 0, 3, 4, 9, 2, 1, 8, 0, 0, 7, 0, 4, 0, 2, 3, 5 (list; constant; graph; refs; listen; history; internal format)
OFFSET

1,5

COMMENTS

a(n) is the infinite sum of the reciprocals of repunits, R_n, with n>0 (A002275) [From Barbarel Tres Mil (barbarel3000(AT)yahoo.es), Dec 06 2009]

REFERENCES

S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 354-361.

LINKS

Harry J. Smith, Table of n, a(n) for n=1,...,2000

S. R. Finch, Digital Search Tree Constants

EXAMPLE

1.10091819083620073637985510165438004320345439787328165635989...

MATHEMATICA

RealDigits[9*N[ Sum[1/(10^k - 1), {k, 1, Infinity}], 120]] [[1]]

A065444=RealDigits[ Block[{$MaxExtraPrecision = 100}, N[9*Sum[(-1 + 10^i)^-1, {i, 1, Infinity}], 130]]][[1]] [From Barbarel Tres Mil (barbarel3000(AT)yahoo.es), Dec 06 2009]

PROG

(PARI) { default(realprecision, 2080); x=9*suminf(k=1, 1/(10^k - 1)); for (n=1, 2000, d=floor(x); x=(x-d)*10; write("b065444.txt", n, " ", d)) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 19 2009]

CROSSREFS

Equals 9*A073668.

A067617 gives the expansion in continued fraction of a(n) [From Barbarel Tres Mil (barbarel3000(AT)yahoo.es), Dec 06 2009]

Sequence in context: A154207 A200101 A084002 * A010169 A113657 A098783

Adjacent sequences:  A065441 A065442 A065443 * A065445 A065446 A065447

KEYWORD

nonn,cons

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Nov 18 2001

EXTENSIONS

More terms from John W. Layman (layman(AT)math.vt.edu), Nov 19 2001

...733 (50th digit) expanded to ...7328165 etc. by Frank Ellermann (hmdmhdfmhdjmzdtjmzdtzktdkztdjz(AT)gmail.com), Feb 23 2002

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Last modified February 17 19:13 EST 2012. Contains 206085 sequences.