A338363 a(n) = n + pi(n) - pi(floor(n/2)), where pi = A000720.

1, 3, 5, 5, 7, 7, 9, 10, 11, 11, 13, 14, 16, 16, 17, 18, 20, 21, 23, 24, 25, 25, 27, 28, 29, 29, 30, 31, 33, 34, 36, 37, 38, 38, 39, 40, 42, 42, 43, 44, 46, 47, 49, 50, 51, 51, 53, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 64, 66, 67, 69, 69, 70, 71, 72, 73, 75, 76, 77, 78, 80, 81

Offset: 1

Author

N. J. A. Sloane, Nov 04 2020

Keywords

• nonn

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000720, A056171, A095117, A282029, A283312, A338362.

Programs

Mathematica

A338363[n_] := PrimePi[n] - PrimePi[n/2] + n;
Array[A338363, 100] (* Paolo Xausa, Jan 30 2024 *)

PARI

a(n) = n + primepi(n) - primepi(n\2); \\ Michel Marcus, Nov 04 2020

Formula

a(n) = n + A056171(n). - Alois P. Heinz, Nov 04 2020