A253608 The binary representation of a(n) is the concatenation of n and the binary complement of n, A035327(n).

2, 9, 12, 35, 42, 49, 56, 135, 150, 165, 180, 195, 210, 225, 240, 527, 558, 589, 620, 651, 682, 713, 744, 775, 806, 837, 868, 899, 930, 961, 992, 2079, 2142, 2205, 2268, 2331, 2394, 2457, 2520, 2583, 2646, 2709, 2772, 2835, 2898, 2961, 3024, 3087, 3150, 3213

Offset

1,1

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Formula

a(n) = (n+1) * (2^BL(n) - 1), where BL(n) is the binary length of n.

Maple

a:= n-> (n+1)*(2^(ilog2(n)+1)-1):
seq(a(n), n=1..50);  # Alois P. Heinz, Jan 08 2015

Mathematica

Array[(# + 1) (2^(Floor@ Log2[#] + 1) - 1) &, 50] (* Michael De Vlieger, Oct 13 2018 *)

Prog

(Python)
for n in range(1, 333):
  print(str((n+1)*(2 ** int.bit_length(int(n))-1)), end=', ')
(PARI) a(n) = (n+1)*(2^#binary(n)-1); \\ Michel Marcus, Jan 08 2015

Crossrefs

Cf. A035327, A036044, A070939.

Sequence in context: A340038 A178312 A347495 * A126977 A102237 A324571

Adjacent sequences: A253605 A253606 A253607 * A253609 A253610 A253611

Keyword

nonn,easy,base

Author

Alex Ratushnyak, Jan 05 2015

Status

approved