A336410 Complement of A336411.

1, 3, 5, 6, 8, 9, 11, 12, 13, 15, 16, 18, 19, 20, 21, 22, 24, 26, 27, 28, 29, 31, 33, 34, 35, 36, 37, 39, 41, 43, 44, 45, 47, 48, 50, 51, 52, 53, 55, 56, 58, 59, 60, 62, 63, 64, 65, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 79, 81, 82, 83, 84, 85, 87, 88

Offset: 1

Author

Clark Kimberling, Sep 06 2020

Keywords

• nonn

Comments

Previous name was: "Numbers k such that prime(k) - oc(k) = 2, where oc(k) is the greatest odd composite < prime(k)".

Crossrefs

Cf. A000040, A014076, A336409, A336411.

Programs

Mathematica

z = 5000; d = Select[Range[2, z], ! PrimeQ@# && OddQ@# &];  (* A014076 *)
f[n_] := Select[d, # < Prime[n] &];
t = Table[Prime[n] - Max[f[n]], {n, 5, 300}]  (* A336409 *)
Flatten[Position[t, 2]]  (* this sequence *)
Flatten[Position[t, 4]]  (* A336411 *)

Formula

a(n) = (A176852(n) - 5)/2. - Hugo Pfoertner, Jul 19 2023

Extensions

Offset corrected by Mohammed Yaseen, Jul 19 2023

New name from Hugo Pfoertner, Jul 20 2023