login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A108321 a(n) = n^2 if n^2 is not the difference of two primes; otherwise a(n) = 0. 0
0, 0, 0, 0, 25, 0, 49, 0, 0, 0, 121, 0, 169, 0, 0, 0, 289, 0, 361, 0, 0, 0, 529, 0, 625, 0, 729, 0, 841, 0, 961, 0, 0, 0, 1225, 0, 1369, 0, 0, 0, 1681, 0, 1849 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

This sequence is also n^2 - A106546

LINKS

Table of n, a(n) for n=0..42.

EXAMPLE

a(4)=0 because the fourth perfect square 16 is the difference between two primes: 19-3. a(5)=25 figures here because the nearest prime greater than 25 is 29 and the difference 29-25 is 4 (an even number >2), thus not a prime; all other greater primes are odd and the difference with 25 will give an even number, thus again not a prime.

CROSSREFS

Cf. A106546, A106564, A098108, A106571.

Sequence in context: A005079 A167624 A181614 * A059062 A179809 A110416

Adjacent sequences: A108318 A108319 A108320 * A108322 A108323 A108324

KEYWORD

easy,nonn

AUTHOR

Alexandre Wajnberg, Jun 30 2005

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 December 5 02:30 EST 2022. Contains 358572 sequences. (Running on oeis4.)