login
This site is supported by donations to The OEIS Foundation.

 

Logo

Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A168068 Array T(n,k) read by antidiagonals: T(n,2k+1) = 2k+1. T(n,2k) = 2^n*k. 2
0, 0, 1, 0, 1, 1, 0, 1, 2, 3, 0, 1, 4, 3, 2, 0, 1, 8, 3, 4, 5, 0, 1, 16, 3, 8, 5, 3, 0, 1, 32, 3, 16, 5, 6, 7, 0, 1, 64, 3, 32, 5, 12, 7, 4, 0, 1, 128, 3, 64, 5, 24, 7, 8, 9, 0, 1, 256, 3, 128, 5, 48, 7, 16, 9, 5, 0, 1, 512, 3, 256, 5, 96, 7, 32, 9, 10, 11, 0, 1, 1024, 3, 512, 5, 192, 7, 64, 9, 20, 11, 6, 0, 1, 2048, 3, 1024, 5 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,9

COMMENTS

The array is constructed multiplying the even-indexed A026741(k) by 2^n, and keeping the odd-indexed A026471(k) as they are.

Connections to the hydrogen spectrum: The squares of the second row are T(1,k)^2 = A001477(k)^2 = A000290(k) which are the denominators of the Lyman lines (see A171522). The squares of the row T(2,k) are in A154615, denominators of the Balmer series. Row T(3,k) is related to A106833 and A061038.

LINKS

Table of n, a(n) for n=0..96.

EXAMPLE

The array starts in row n=0 with columns k>=0 as:

0,1,1,3,2,5,3,7,4, A026741

0,1,2,3,4,5,6,7,8, A001477

0,1,4,3,8,5,12,7,16, A022998

0,1,8,3,16,5,24,7,32, A144433

0,1,16,3,32,5,48,7,64,

0,1,32,3,64,5,96,7,128,

MAPLE

A168068 := proc(n, k) if type(k, 'odd') then k; else 2^(n-1)*k ; end if; end proc: # R. J. Mathar, Jan 22 2011

CROSSREFS

Sequence in context: A055137 A143325 A128888 * A163575 A163465 A004443

Adjacent sequences:  A168065 A168066 A168067 * A168069 A168070 A168071

KEYWORD

nonn,easy,tabl

AUTHOR

Paul Curtz, Nov 18 2009

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified August 23 06:19 EDT 2014. Contains 245977 sequences.