A014238 a(n) = (n-th number that is 1 or prime) - (n-th composite number).

-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

G. C. Greubel, Table of n, a(n) for n = 1..1000

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

Cf. A000045, A018252.

Sequence in context: A178783 A156671 A072006 * A275719 A014250 A155078

Adjacent sequences: A014235 A014236 A014237 * A014239 A014240 A014241

Keyword

sign

Author

Clark Kimberling

Status

approved