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A064722
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a(1) = 0; for n >= 2, a(n) = n - (largest prime <= n).
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17
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0, 0, 0, 1, 0, 1, 0, 1, 2, 3, 0, 1, 0, 1, 2, 3, 0, 1, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 0, 1, 0, 1, 2, 3
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OFFSET
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1,9
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LINKS
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FORMULA
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a(n) = 0 iff n is 1 or a prime.
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EXAMPLE
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a(26) = 26 - 23 = 3, a(37) = 37 - 37 = 0.
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MAPLE
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0, seq(n - prevprime(n+1), n=2..100); # Robert Israel, Aug 25 2014
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MATHEMATICA
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Join[{0}, Table[n-NextPrime[n+1, -1], {n, 2, 110}]] (* Harvey P. Dale, Aug 23 2011 *)
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PROG
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(PARI) { for (n = 1, 1000, if (n>1, a=n - precprime(n), a=0); write("b064722.txt", n, " ", a) ) } \\ Harry J. Smith, Sep 23 2009
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CROSSREFS
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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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