|
Search: id:A108321
|
|
|
| A108321 |
|
a(n) = n^2 if n^2 is not the difference of two primes; otherwise a(n) = 0. |
|
+0
1
|
|
| 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; listen)
|
|
|
OFFSET
|
0,5
|
|
|
COMMENT
|
This sequence is also n^2 - A106546
|
|
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: A068741 A005079 A167624 this_sequence A059062 A110416 A028848
Adjacent sequences: A108318 A108319 A108320 this_sequence A108322 A108323 A108324
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Alexandre Wajnberg (alexandre.wajnberg(AT)ulb.ac.be), Jun 30 2005
|
|
|
Search completed in 0.002 seconds
|
