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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

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Last modified October 22 18:02 EDT 2019. Contains 328319 sequences. (Running on oeis4.)