A246831 a(n) is the concatenation of n and 3n in binary.

0, 7, 22, 57, 76, 95, 210, 245, 280, 315, 350, 737, 804, 871, 938, 1005, 1072, 1139, 1206, 1273, 1340, 1407, 2882, 3013, 3144, 3275, 3406, 3537, 3668, 3799, 3930, 4061, 4192, 4323, 4454, 4585, 4716, 4847, 4978, 5109, 5240, 5371, 5502, 11137, 11396, 11655

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..10000

Formula

a(n) = A246830(2n,n).

Example

a(0) = (0|0)_2 = 0.
a(1) = (1|11)_2 = 7.
a(2) = (10|110)_2 = 22.
a(3) = (11|1001)_2 = 57.
a(4) = (100|1100)_2 = 76.
a(5) = (101|1111)_2 = 95.

Maple

f:= proc(i, j) local r, h, k; r:=0; h:=0; k:=j;
      while k>0 do r:=r+2^h*irem(k, 2, 'k'); h:=h+1 od; k:=i;
      while k>0 do r:=r+2^h*irem(k, 2, 'k'); h:=h+1 od; r
    end:
a:= n-> f(n, 3*n):
seq(a(n), n=0..60);

Prog

(Python)
def A246831(n):
....return int(bin(n)[2:]+bin(3*n)[2:], 2) # Chai Wah Wu, Sep 05 2014

Crossrefs

Cf. A246830. Column k=3 of A246834.

Sequence in context: A188377 A213585 A308579 * A354430 A122238 A101289

Adjacent sequences: A246828 A246829 A246830 * A246832 A246833 A246834

Keyword

nonn,base

Author

Alois P. Heinz, Sep 04 2014

Status

approved