Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A128867
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A128867 Let f(i) = prime( f(i - 1) (modulo 10^n) ) with f(0) = 1; a(n) is the length of the period of the sequence f(i). +0
1
4, 5, 31, 106, 53, 582, 318, 9528, 11201, 19174 (list; graph; listen)
OFFSET

1,1

EXAMPLE

For a(1), the sequence is 1, 2, 3, 5, 11, 2, 3, 5, 11, 2, 3,

5, 11, ... The sequence has period {2, 3, 5, 11} so a(1) = 4.

For a(2) see the A112279: 1, 2, 3, 5, 11, 31, 127, 103, 5,

11, 31, 127, 103, 5, 11, ..., . This sequence has a cyclic length of 5.

MATHEMATICA

f[n_] := Block[{k = 1, a}, a[0] = 1; a[i_] := a[i] = Prime[Mod[a[i - 1], 10^n]]; While[t = Table[a[i], {i, 0, k - 1}]; MemberQ[t, a[k]] == False, k++ ]; k + 1 - Flatten[ Position[ t, a[k]]][[1]]]; Array[ f, 10]

CROSSREFS

Sequence in context: A041273 A047169 A124482 this_sequence A013468 A041907 A151450

Adjacent sequences: A128864 A128865 A128866 this_sequence A128868 A128869 A128870

KEYWORD

nonn,more

AUTHOR

Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 05 2007

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified December 7 08:40 EST 2009. Contains 170430 sequences.


AT&T Labs Research