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A072823 Numbers that are not the sum of two powers of 2. 5
1, 7, 11, 13, 14, 15, 19, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 35, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 67, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 97 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

1 and integers with three or more 1-bits in their binary expansion. - Vladimir Baltic, Jul 23 2002

A073267(a(n)) = 0. [Reinhard Zumkeller, Mar 07 2012]

Appears to be the numbers k >1 for which there exist an x and y (x>y) such that x OR y = k, x+y != k, and x<k. - Gary Detlefs, Jun 02 2014

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

MAPLE

f:= x -> convert(convert(x, base, 2), `+`)>2:

{1} union select(f, {$2..1000}); # Robert Israel, Jun 08 2014

MATHEMATICA

Join[{1}, Select[Range[100], DigitCount[#, 2, 1] >= 3&]] (* Jean-Fran├žois Alcover, Mar 08 2019 *)

PROG

(Haskell)

a072823 n = a072823_list !! (n-1)

a072823_list = tail $ elemIndices 0 a073267_list

-- Reinhard Zumkeller, Mar 07 2012

CROSSREFS

Cf. A048645, A000027.

Sequence in context: A275516 A084451 A091901 * A336004 A110547 A279622

Adjacent sequences:  A072820 A072821 A072822 * A072824 A072825 A072826

KEYWORD

nonn

AUTHOR

Jeremy Gardiner, Jul 21 2002

STATUS

approved

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Last modified January 17 17:03 EST 2021. Contains 340247 sequences. (Running on oeis4.)