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A108321 a(n) = n^2 if n^2 is not the difference of two primes; otherwise a(n) = 0. 0

%I #4 Mar 31 2012 14:11:37

%S 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,

%T 729,0,841,0,961,0,0,0,1225,0,1369,0,0,0,1681,0,1849

%N a(n) = n^2 if n^2 is not the difference of two primes; otherwise a(n) = 0.

%C This sequence is also n^2 - A106546

%e 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.

%Y Cf. A106546, A106564, A098108, A106571.

%K easy,nonn

%O 0,5

%A _Alexandre Wajnberg_, Jun 30 2005

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