|
Search: id:A043569
|
|
|
| A043569 |
|
Numbers n such that base 2 representation has exactly 2 runs. |
|
+0
4
|
|
| 2, 4, 6, 8, 12, 14, 16, 24, 28, 30, 32, 48, 56, 60, 62, 64, 96, 112, 120, 124, 126, 128, 192, 224, 240, 248, 252, 254, 256, 384, 448, 480, 496, 504, 508, 510, 512, 768, 896, 960, 992, 1008, 1016, 1020, 1022, 1024, 1536, 1792, 1920, 1984, 2016, 2032, 2040, 2044
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Numbers n such that binary representation contains the bit string "10" but not "01". Subsequence of A062289; set difference A062289 minus A101082. - Rick L. Shepherd (rshepherd2(AT)hotmail.com), Nov 29 2004
Mersenne numbers (A000225) times powers of 2 (A000079). Therefore this sequence contains the even perfect numbers (A000396). - Alonso Delarte (alonso.delarte(AT)gmail.com), Apr 21 2006
|
|
FORMULA
|
This sequence is twice A023758. - Franklin T. Adams-Watters, Apr 21 2006
|
|
MAPLE
|
a:=proc(n) local nn, nd: nn:=convert(n, base, 2): nd:={seq(nn[j]-nn[j-1], j=2..nops(nn))}: if n=2 then 2 elif nd={0, 1} then n else fi end: seq(a(n), n=1..2100); - Emeric Deutsch, Apr 21 2006
a:=proc(n) local n2, d: n2:=convert(n, base, 2): d:={seq(n2[j]-n2[j-1], j=2..nops(n2))}: if n=2 then 2 elif d={0, 1} then n else fi end: seq(a(n), n=1..2100); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 22 2006
|
|
MATHEMATICA
|
Take[Sort[Flatten[Table[(2^x - 1)*(2^y), {x, 32}, {y, 32}]]], 54] - Alonso Delarte (alonso.delarte(AT)gmail.com), Apr 21 2006
|
|
CROSSREFS
|
Cf. A062289, A101082.
Sequence in context: A043748 A043756 A043765 this_sequence A010063 A089623 A089681
Adjacent sequences: A043566 A043567 A043568 this_sequence A043570 A043571 A043572
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
Clark Kimberling (ck6(AT)evansville.edu)
|
|
EXTENSIONS
|
More terms from Rick L. Shepherd (rshepherd2(AT)hotmail.com), Nov 29 2004
|
|
|
Search completed in 0.002 seconds
|
