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A108321
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a(n) = n^2 if n^2 is not the difference of two primes; otherwise a(n) = 0.
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0
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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
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OFFSET
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0,5
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COMMENTS
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This sequence is also n^2 - A106546
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LINKS
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EXAMPLE
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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.
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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