login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A165274 Table read by antidiagonals: T(n, k) is the k-th number with n-1 even-power summands in its base 2 representation. 1

%I

%S 2,8,1,10,3,5,32,4,7,21,34,6,13,23,85,40,9,15,29,87,341,42,11,17,31,

%T 93,343,1365,128,12,19,53,95,349,1367,5461,130,14,20,55,117,351,1373,

%U 5463,21845,136,16,22,61,119,373,1375,5469,21847,87381,138,18,25,63

%N Table read by antidiagonals: T(n, k) is the k-th number with n-1 even-power summands in its base 2 representation.

%C For n>=0, row n is the ordered sequence of positive integers m such that the number of even powers of 2 in the base 2 representation of m is n.

%C Every positive integer occurs exactly once in the array, so that as a sequence it is a permutation of the positive integers.

%C For odd powers, see A165275.

%C For the number of even powers of 2 in the base 2 representation of n, see A139351; for odd, see A139352.

%C Essentially, (Row 0)=A062880, (Row 1)=A158705, (Column 1)=A002450, also possibly (Column 2)=A163832.

%e Northwest corner:

%e 2....8...10...32...34...40...42...129

%e 1....3....4....6....9...11...12...14

%e 5....7...13...15...17...19...20...22

%e 21..23...29...31...53...55...61...63

%e Examples:

%e 40 = 32 + 8 = 2^5 + 2^3, so that 40 is in row 0.

%e 13 = 8 + 4 + 1 = 2^3 + 2^2 + 2^0, so that 13 is in row 2.

%t f[n_] := Total[(Reverse@IntegerDigits[n, 2])[[1 ;; -1 ;; 2]]]; T = GatherBy[ SortBy[Range[10^5], f], f]; Table[Table[T[[n - k + 1, k]], {k, n, 1, -1}], {n, 1, Length[T]}] // Flatten (* _Amiram Eldar_, Feb 04 2020*)

%Y Cf. A139351, A139352, A165275, A165276, A165277, A165278, A165279.

%K nonn,tabl

%O 1,1

%A _Clark Kimberling_, Sep 12 2009

%E More terms from _Amiram Eldar_, Feb 04 2020

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 7 13:36 EDT 2020. Contains 333305 sequences. (Running on oeis4.)