A243615 Numbers n whose digital sum equals the number of binary digits in its binary expansion.

1, 2, 13, 23, 33, 42, 51, 60, 70, 106, 115, 124, 134, 143, 152, 161, 170, 206, 215, 224, 233, 242, 251, 261, 270, 306, 315, 324, 333, 342, 351, 360, 405, 414, 423, 432, 441, 450, 504, 514, 523, 532, 541, 550, 604, 613, 622, 631, 640, 703, 712, 721, 730, 802, 811, 820

Offset

1,2

Links

Andreas Boe, Table of n, a(n) for n = 1..10000

Example

134 -> 1+3+4=8  134=10000110 -> Eight bits.

Mathematica

Select[Range[10^3], Total@ IntegerDigits@ # == 1 + Floor@ Log2@ # &] (* Michael De Vlieger, Nov 05 2018 *)
Select[Range[1000], Total[IntegerDigits[#]]==IntegerLength[#, 2]&] (* Harvey P. Dale, May 30 2021 *)

Prog

(PARI) isok(n) = sumdigits(n) == #binary(n); \\ Michel Marcus, Jun 08 2014

Crossrefs

Cf. A000120, A007953.

Sequence in context: A118796 A234218 A171794 * A243617 A045389 A243621

Adjacent sequences: A243612 A243613 A243614 * A243616 A243617 A243618

Keyword

nonn,base

Author

Andreas Boe, Jun 07 2014

Status

approved