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 A014237 a(n) = (n-th prime) - (n-th nonprime). 4
 1, -1, -1, -1, 2, 3, 5, 5, 8, 13, 13, 17, 20, 21, 23, 28, 33, 34, 39, 41, 41, 46, 49, 54, 61, 63, 64, 67, 67, 69, 82, 85, 89, 90, 99, 100, 105, 109, 112, 117, 122, 123, 131, 131, 134, 135, 146, 157, 159, 160, 163, 167, 167, 176, 181, 186, 191, 191, 196 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS a(n) = A000040(n) - A018252(n). - Reinhard Zumkeller, Apr 30 2014 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 MATHEMATICA nonPrime[n_Integer] := FixedPoint[n + PrimePi@# &, n+PrimePi@n]; Table[Prime[n] - nonPrime[n], {n, 1, 70}] (* G. C. Greubel, Jun 22 2019 *) PROG (Haskell) a014237 n = a000040 n - a018252 n  -- Reinhard Zumkeller, Apr 30 2014 (Python) from sympy import prime, composite def A014237(n):     return 1 if n == 1 else prime(n)-composite(n-1) # Chai Wah Wu, Dec 27 2018 CROSSREFS Cf. A038529, A026233, A127118. Sequence in context: A287919 A138181 A006447 * A033885 A053079 A326061 Adjacent sequences:  A014234 A014235 A014236 * A014238 A014239 A014240 KEYWORD sign AUTHOR STATUS approved

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Last modified August 20 07:48 EDT 2019. Contains 326143 sequences. (Running on oeis4.)