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A215473
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Number of prime quadruples with smallest member < 2^n.
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0
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0, 0, 1, 2, 2, 2, 3, 4, 4, 5, 7, 10, 11, 16, 23, 28, 43, 62, 106, 177, 309, 483, 795, 1305, 2105, 3525, 5923, 10096, 17259, 30004
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OFFSET
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1,4
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COMMENTS
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Prime quadruples (A007530) are numbers n such that n, n+2, n+6, n+8 are all prime.
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LINKS
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EXAMPLE
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a(3) = 1 because there is only one prime quadruple below 2^3, namely {5, 7, 11, 13}.
a(4) = 2 because there are two prime quadruples below 2^4: the aforementioned and {11, 13, 17, 19}.
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MATHEMATICA
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CROSSREFS
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Cf. A050258, similar definition but with powers of 10 instead of 2.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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