login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A127649 A127648 * A054523 as infinite lower triangular matrices. 1
1, 2, 2, 6, 0, 3, 8, 4, 0, 4, 20, 0, 0, 0, 5, 12, 12, 6, 0, 0, 6, 42, 0, 0, 0, 0, 0, 7, 32, 16, 0, 8, 0, 0, 0, 8, 54, 0, 18, 0, 0, 0, 0, 0, 9, 40, 40, 0, 0, 10, 0, 0, 0, 0, 10, 110, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 48, 24, 24, 24, 0, 12, 0, 0, 0, 0, 0, 12, 156, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13, 84 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Natural number transform of A054523.

Row sums = n^2, left column = A002618

LINKS

Table of n, a(n) for n=1..92.

FORMULA

T(n,k)=n*A054523(n,k). - R. J. Mathar, Nov 01 2007

EXAMPLE

First few rows of the triangle are:

1;

2, 2;

6, 0, 3;

8, 4, 0, 4;

20, 0, 0, 0, 5;

12, 12, 6, 0, 0, 6;

42, 0, 0, 0, 0, 0, 7;

...

MAPLE

A054523 := proc(n, k) if n mod k = 0 then numtheory[phi](n/k) ; else 0 ; fi ; end: A127649 := proc(n, k) A054523(n, k)*n ; end: for n from 1 to 20 do for k from 1 to n do printf("%d, ", A127649(n, k)) ; od: od: # R. J. Mathar, Nov 01 2007

CROSSREFS

Cf. A127648, A002618, A054523.

Sequence in context: A163119 A091085 A011144 * A274440 A199220 A047916

Adjacent sequences: A127646 A127647 A127648 * A127650 A127651 A127652

KEYWORD

nonn,tabl,easy

AUTHOR

Gary W. Adamson, Jan 22 2007

EXTENSIONS

More terms from R. J. Mathar, Nov 01 2007

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 6 15:54 EST 2022. Contains 358644 sequences. (Running on oeis4.)