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A067532
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Numbers n such that n + number of divisors is a prime.
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3
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1, 3, 4, 5, 11, 15, 17, 27, 29, 33, 39, 41, 55, 57, 59, 64, 69, 71, 85, 93, 100, 101, 105, 107, 123, 133, 137, 145, 149, 159, 165, 175, 177, 179, 187, 189, 191, 197, 219, 227, 231, 235, 237, 239, 245, 247, 253, 255, 259, 265, 267, 269, 273, 275, 281, 285, 303
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OFFSET
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1,2
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COMMENTS
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Smaller of the twin primes (A001359) is a term.
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LINKS
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EXAMPLE
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a(1)=1 (1+d(1)=1+1=2=prime); a(2)=3 (3+d(3)=3+2=5=prime).
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MAPLE
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with(numtheory): for n from 3 to 500 do if isprime(n+tau(n)) then printf(`%d, `, n) fi:od: # James A. Sellers, Feb 18 2002
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MATHEMATICA
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a067532[n_] := Select[Range[n], PrimeQ[# + DivisorSigma[0, #]] &]; a067532[303] (* Michael De Vlieger, Dec 22 2014 *)
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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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EXTENSIONS
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STATUS
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approved
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