login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A160440 Smaller member of a pair (p,q) of cousin primes such that p and q are in different centuries. 9
97, 397, 499, 1297, 1597, 1999, 2797, 3697, 4999, 6199, 6997, 7699, 9199, 10099, 10597, 12097, 13099, 16699, 18397, 20899, 21397, 21499, 21799, 23197, 23599, 25999, 26497, 27697, 27799, 27997, 32299, 32797, 33199, 34297, 35797, 38197, 38299, 39499, 42697 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Sequence is probably infinite.

It appears that every integer occurs as the difference round((a(n+1)-a(n))/100); all numbers 1..298 occur as these differences for a(n) < 1000000000. - Hartmut F. W. Hoft, May 18 2017

LINKS

Table of n, a(n) for n=1..39.

FORMULA

{A023200(n): [A023200(n)/100] <> [A046132(n)/100]}, where [..]=floor(..).

EXAMPLE

Cousin primes 1597 and 1601 are in successive (that is 16th and 17th) centuries.

MATHEMATICA

a160440[n_] := Map[Last, Select[Map[{NextPrime[#, 1], NextPrime[#, -1]}&, Range[100, n, 100]], First[#]-Last[#]==4&]]

a160440[43000] (* data *) (* Hartmut F. W. Hoft, May 18 2017 *)

CROSSREFS

Cf. A046132, A160370

Sequence in context: A031927 A174338 A050666 * A107213 A157331 A142834

Adjacent sequences:  A160437 A160438 A160439 * A160441 A160442 A160443

KEYWORD

nonn

AUTHOR

Ki Punches, May 13 2009

EXTENSIONS

Edited by R. J. Mathar, May 14 2009

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 20 11:38 EDT 2019. Contains 324234 sequences. (Running on oeis4.)