The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A086407 a[1]=1; a[n+1]=a[n]-1 if mod[prime[a[n]],6]=5, else a[n+1]=a[n]+4. 2
1, 5, 4, 8, 12, 16, 15, 14, 18, 22, 26, 25, 29, 33, 32, 31, 35, 34, 38, 42, 46, 50, 54, 53, 57, 56, 55, 54, 53, 57, 56, 55, 54, 53, 57, 56, 55, 54, 53, 57, 56, 55, 54, 53, 57, 56, 55, 54, 53, 57, 56, 55, 54 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
There is a cycle ...54,53,57,56,55,54,...
LINKS
EXAMPLE
a(3)=4 because a(2)=5, prime[5]=11=1 (mod 6) and a(3)=a(2)-1
MATHEMATICA
b=1; Prepend[Table[b+=If[Mod[Prime[b], 6]\[Equal]5, -1, 4], {i, 32}], 1]
nxt[a_]:=If[Mod[Prime[a], 6]==5, a-1, a+4]; NestList[nxt, 1, 60] (* Harvey P. Dale, May 29 2013 *)
CROSSREFS
Sequence in context: A051555 A309543 A187891 * A160427 A343244 A215337
KEYWORD
easy,nonn
AUTHOR
Zak Seidov, Jul 18 2003
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 27 15:55 EDT 2024. Contains 372880 sequences. (Running on oeis4.)