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A106571
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Indices n of perfect squares n^2 which are not the difference of two primes.
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16
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5, 7, 11, 13, 17, 19, 23, 25, 27, 29, 31, 35, 37, 41, 43, 47, 49, 51, 53, 55, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 83, 85, 87, 89, 91, 93, 95, 97, 101, 103, 107, 109, 113, 115, 119, 121, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 149, 151, 153, 155
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OFFSET
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1,1
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COMMENTS
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Also, n such that 1+n^2 is a nontotient (A005277). - T. D. Noe, Sep 13 2007
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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FORMULA
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a(n) = SQRT(A106564(n)).
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EXAMPLE
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a(3)=11 because the third square which is not the difference of two primes (121=11^2) is the 11-th one in the succession of the perfect squares (thus index 11).
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CROSSREFS
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Cf. A106544-A106548, A106562-A106564, A106573-A106575, A106577.
Cf. A067201 (n such that n^2+2 is prime)
Sequence in context: A111906 A101550 A136801 * A067291 A007310 A069040
Adjacent sequences: A106568 A106569 A106570 * A106572 A106573 A106574
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KEYWORD
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easy,nonn
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AUTHOR
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Alexandre Wajnberg, May 09 2005
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EXTENSIONS
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Extended by Ray Chandler, May 12 2005
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STATUS
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approved
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