login
A014238
a(n) = (n-th number that is 1 or prime) - (n-th composite number).
1
-3, -4, -5, -4, -3, -1, -1, 2, 3, 5, 9, 10, 15, 17, 18, 21, 26, 31, 31, 35, 38, 39, 44, 47, 51, 58, 61, 61, 63, 64, 67, 79, 82, 87, 88, 97, 97, 102, 107, 110, 115, 119, 119, 128, 129, 132, 133, 143, 154, 157, 157, 159, 164, 165, 174, 179, 183, 188, 189
OFFSET
1,1
LINKS
MATHEMATICA
nonPrime[n_Integer] := FixedPoint[n+PrimePi@# &, n+PrimePi@n]; Join[{-3}, Table[Prime[n] - nonPrime[n+2], {n, 1, 70}]] (* G. C. Greubel, Jun 22 2019 *)
CROSSREFS
Sequence in context: A178783 A156671 A072006 * A275719 A014250 A155078
KEYWORD
sign
STATUS
approved