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A069848
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Number of distinct primes obtained by inserting a 7 at all possible places in n. This includes prefixing as well as suffixing.
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9
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2, 0, 2, 1, 0, 1, 0, 0, 2, 1, 0, 1, 2, 0, 1, 1, 0, 0, 3, 0, 1, 1, 0, 0, 1, 0, 2, 0, 0, 1, 1, 0, 3, 1, 0, 1, 0, 0, 3, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 2, 0, 0, 1, 1, 0, 2, 1, 0, 1, 2, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 2, 1, 0, 1, 1, 0, 1, 1, 0, 1, 2, 0, 1, 0, 0, 0, 1, 0, 0
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OFFSET
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1,1
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LINKS
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EXAMPLE
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MATHEMATICA
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Table[ Count[ PrimeQ[ Union[ FromDigits /@ Table[ Insert[ IntegerDigits[n], 7, j], {j, 1, Floor[ Log[10, n] + 2]}]]], True], {n, 1, 105}]
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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