A246358 Numbers k such that d(r,k) = 1 and d(s,k) = 0, where d(x,k) = k-th binary digit of x, r = {sqrt(2)}, s = {sqrt(3)}, and { } = fractional part.

2, 13, 18, 26, 27, 31, 34, 35, 36, 39, 40, 43, 44, 46, 50, 53, 65, 68, 71, 73, 77, 79, 80, 84, 87, 94, 95, 97, 103, 110, 112, 114, 118, 123, 124, 126, 127, 132, 133, 135, 142, 143, 145, 146, 152, 155, 156, 160, 171, 174, 176, 180, 192, 196, 197, 205, 206

Offset

1,1

Comments

Every positive integer lies in exactly one of these: A246356, A246357, A246358, A247356.

Links

Clark Kimberling, Table of n, a(n) for n = 1..1000

Example

{sqrt(2)} has binary digits 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1,...
{sqrt(3)} has binary digits 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0,..
so that a(1) = 2 and a(2) = 13.

Mathematica

z = 500; r = FractionalPart[Sqrt[2]]; s = FractionalPart[Sqrt[3]];
u = Flatten[{ConstantArray[0, -#[[2]]], #[[1]]}] &[RealDigits[r, 2, z]]
v = Flatten[{ConstantArray[0, -#[[2]]], #[[1]]}] &[RealDigits[s, 2, z]]
t1 = Table[If[u[[n]] == 0 && v[[n]] == 0, 1, 0], {n, 1, z}];
t2 = Table[If[u[[n]] == 0 && v[[n]] == 1, 1, 0], {n, 1, z}];
t3 = Table[If[u[[n]] == 1 && v[[n]] == 0, 1, 0], {n, 1, z}];
t4 = Table[If[u[[n]] == 1 && v[[n]] == 1, 1, 0], {n, 1, z}];
Flatten[Position[t1, 1]]  (* A246356 *)
Flatten[Position[t2, 1]]  (* A246357 *)
Flatten[Position[t3, 1]]  (* A246358 *)
Flatten[Position[t4, 1]]  (* A247356 *)

Crossrefs

Cf. A247454, A246356, A246357, A247356.

Sequence in context: A191765 A063615 A297837 * A262688 A020585 A038943

Adjacent sequences: A246355 A246356 A246357 * A246359 A246360 A246361

Keyword

nonn,easy,base

Author

Clark Kimberling, Sep 17 2014

Status

approved