A360396 Intersection of A356133 and A360392.

7, 11, 17, 20, 25, 29, 32, 38, 43, 47, 53, 56, 62, 67, 71, 74, 79, 83, 89, 92, 97, 101, 104, 110, 115, 119, 122, 127, 131, 137, 140, 146, 151, 155, 161, 164, 169, 173, 176, 182, 187, 191, 197, 200, 206, 211, 215, 218, 223, 227, 233, 236, 242, 247, 251, 257

Offset

1,1

Comments

This is the third of four sequences that partition the positive integers. Starting with a general overview, suppose that u = (u(n)) and v = (v(n)) are increasing sequences of positive integers. Let u' and v' be their complements, and assume that the following four sequences are infinite:

(1) u ^ v = intersection of u and v (in increasing order);

(2) u ^ v';

(3) u' ^ v;

(4) u' ^ v'.

Every positive integer is in exactly one of the four sequences. The limiting densities of these four sequences are 4/9, 2/9, 2/9, and 1/9, respectively.

For A360396, u, v, u', v', are sequences obtained from the Thue-Morse sequence, A026430, as follows:

u = A026530 = (1,3,5,6,8,9,10, 12, ... ) = partial sums of A026430

u' = A356133 = (2,4,7,11,13,17, 20, ... ) = complement of u

v = u + 1 = A285954, except its initial 1

v' = complement of v.

Links

Table of n, a(n) for n=1..56.

Example

(1)  u ^ v = (3, 5, 8, 10, 12, 14, 16, 18, 21, 23, 26, 28, 30, 33, ...) =  A360394
(2)  u ^ v' = (1, 6, 9, 15, 19, 24, 27, 31, 36, 42, 45, 51, 55, 60, ...) =  A360395
(3)  u' ^ v = (7, 11, 17, 20, 25, 29, 32, 38, 43, 47, 53, 56, 62, ...) = A360396
(4)  u' ^ v' = (2, 4, 13, 22, 34, 40, 49, 58, 64, 76, 85, 94, 106, ...) = A360397

Mathematica

z = 400;
u = Accumulate[1 + ThueMorse /@ Range[0, z]];   (* A026430 *)
u1 = Complement[Range[Max[u]], u];  (* A356133 *)
v = u + 2 ; (* A360392 *)
v1 = Complement[Range[Max[v]], v];  (* A360393 *)
Intersection[u, v]    (* A360394 *)
Intersection[u, v1]   (* A360395 *)
Intersection[u1, v]   (* A360396 *)
Intersection[u1, v1]  (* A360397 *)

Crossrefs

Cf. A026430, A356133, A360392-A360395, A360397-A360405.

Sequence in context: A339954 A260893 A352630 * A299978 A131229 A092737

Adjacent sequences: A360393 A360394 A360395 * A360397 A360398 A360399

Keyword

nonn,easy

Author

Clark Kimberling, Feb 05 2023

Status

approved