

A247345


a(1) = 16. For n > 1, a(n) is the position of the first occurrence of a(n1) after the decimal point in the decimal expansion of Pi.


1



16, 40, 70, 96, 180, 3664, 24717, 15492, 84198, 65489, 3725, 16974, 41702, 3788, 5757, 1958, 14609, 62892, 44745, 9385, 169, 40, 70, 96, 180, 3664, 24717, 15492, 84198, 65489, 3725, 16974, 41702, 3788, 5757, 1958, 14609, 62892, 44745, 9385, 169, 40, 70, 96
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

After the first term, the sequence enters a repeating cycle of length 20.
According to the information on the website of Anderson, this sequence was discovered earlier by Dan Sikorsky.
First element a(1) = 61 leads after seven steps 61, 219, 716, 39, 43, 23, 16, ... into the same repeating cycle, same with a(1) = 71 after five steps 71, 39, 43, 23, 16, ...  Martin Renner, Feb 22 2020


LINKS

Table of n, a(n) for n=1..44.
D. Andersen, Loop Sequences within Pi, The PiSearch Page.


MATHEMATICA

L={16}; pi=ToString[ FromDigits@ RealDigits[Pi3, 10, 10^5 ][[1]]]; Do[
AppendTo[L, StringPosition[ pi, ToString@ Last@ L, 1][[1, 1]]], {23}]; L (* Giovanni Resta, Jul 26 2015 *)


CROSSREFS

Cf. A000796, A097614.
Sequence in context: A132161 A316562 A221684 * A332519 A177723 A174321
Adjacent sequences: A247342 A247343 A247344 * A247346 A247347 A247348


KEYWORD

nonn,base


AUTHOR

Felix FrÃ¶hlich, Jul 26 2015


STATUS

approved



