

A098325


Recurrence sequence based on positions of digits in decimal places of sqrt(Pi).


6



0, 9, 10, 75, 39, 218, 78, 61, 45, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4
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OFFSET

0,2


LINKS

Table of n, a(n) for n=0..82.


FORMULA

a(1)=0, p(i)=position of first occurrence of a(i) in decimal places of sqrt(Pi), a(i+1)=p(i).


EXAMPLE

sqrt(Pi)=1.7724538509055...
So for example, a(2)=9 because 9th decimal place of sqrt(Pi) is 0.
a(3)=10 because 10th decimal place of sqrt(Pi) is 9, a(4)=75 because 10 appears at the 75th to 76th decimal places and so on.
This sequence, like the one for Zeta(3) (A098290), repeats after just a few terms once the sequence hits 4 at position 4.


MAPLE

with(StringTools): Digits:=1000: G:=convert(evalf(sqrt(Pi)), string): a[0]:=0: for n from 1 to 15 do a[n]:=Search(convert(a[n1], string), G)2:printf("%d, ", a[n1]):od: # Nathaniel Johnston, Apr 30 2011


CROSSREFS

Other recurrence sequences: A097614 for Pi, A098266 for e, A098289 for log(2), A098290 for Zeta(3), A098319 for 1/Pi, A098320 for 1/e, A098321 for gamma, A098322 for G, A098323 for 1/G, A098324 for Golden Ratio, phi. A002167 for digits of sqrt(Pi).
Sequence in context: A048070 A167708 A135332 * A101242 A033046 A025635
Adjacent sequences: A098322 A098323 A098324 * A098326 A098327 A098328


KEYWORD

easy,nonn,base


AUTHOR

Mark Hudson (mrmarkhudson(AT)hotmail.com), Sep 03 2004


STATUS

approved



