

A197123


a(n) is the first ndigit substring to repeat in the decimal expansion of Pi.


1



1, 26, 592, 582, 60943, 949129, 8530614, 52637962, 201890888, 4392366484, 89879780761, 756130190263, 3186120489507, 18220874234996, 276854551127715, 8230687217052243, 93415455347042966, 13724950651727463
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OFFSET

1,2


COMMENTS

a(4) is written in the sequence as a 3digit number 582 because the repeating substring is the 4digit number 0582.
a(18) should also have a leading zero: 013724950651727463. This value starts at digit 378,355,223 and at digit 1,982,424,643. This computation was performed by Richard Tobin.  Clive Tooth, Mar 06 2012


LINKS

Table of n, a(n) for n=1..18.
Dave Andersen, The PiSearch Page.
David H. Bailey, The computation of pi to 29,360,000 decimal digits using Borweins' quartically convergent algorithm, Mathematics of Computation 50 (1988), pp. 283296.


EXAMPLE

For n=2 the a(2)=26 solution is because if we look at all the 2digit substrings 14,41,15,59,92,26,... of the decimal expansion of Pi=3.1415926535897932384626 we find that the first 2digit substring to appear twice is 26.


CROSSREFS

Cf. A000796 (Pi), A159345 (the number of digits of Pi required to include the repeated string).
Sequence in context: A265461 A257518 A160059 * A203598 A262076 A057010
Adjacent sequences: A197120 A197121 A197122 * A197124 A197125 A197126


KEYWORD

base,nonn


AUTHOR

Peter de Rivaz, Oct 10 2011


EXTENSIONS

a(16)a(18) from Clive Tooth, Mar 06 2012


STATUS

approved



