A209064 Numbers n whose divisors, when expressed in binary, have lengths 1 to tau(n).

1, 2, 3, 4, 8, 10, 14, 15, 16, 32, 44, 50, 52, 63, 64, 128, 136, 152, 170, 184, 190, 230, 231, 232, 238, 248, 250, 255, 256, 484, 512, 592, 656, 688, 752, 848, 944, 976, 1024, 2048, 2144, 2272, 2312, 2336, 2528, 2656, 2848, 2888, 2890, 2948, 3104, 3124, 3212

Offset

1,2

Comments

Subsequence of A135772 (numbers having equal number of divisors and binary digits).

Supersequence of A000079 (powers of 2).

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Example

Divisors of n in base 2 (k-th divisor contains k digits):
n=1:   1;
n=16:  1, 10, 100, 1000, 10000;
n=230: 1, 10, 101, 1010, 10111, 101110, 1110011, 11100110.

Mathematica

Join[{1}, Select[Range[4000], Union[Differences[Length /@ IntegerDigits[Divisors[#], 2]]] == {1} &]] (* T. D. Noe, Mar 12 2012 *)

Crossrefs

Cf. A135772.

Sequence in context: A190896 A365018 A135772 * A222264 A051783 A033083

Adjacent sequences: A209061 A209062 A209063 * A209065 A209066 A209067

Keyword

nonn,base

Author

Jaroslav Krizek, Mar 04 2012

Status

approved