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

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A157632 Triangle T(n,m) read by rows: 1 in column m=0 and on the diagonal, else 3*n*m*(n-m). 0
1, 1, 1, 1, 6, 1, 1, 18, 18, 1, 1, 36, 48, 36, 1, 1, 60, 90, 90, 60, 1, 1, 90, 144, 162, 144, 90, 1, 1, 126, 210, 252, 252, 210, 126, 1, 1, 168, 288, 360, 384, 360, 288, 168, 1, 1, 216, 378, 486, 540, 540, 486, 378, 216, 1, 1, 270, 480, 630, 720, 750, 720, 630, 480, 270, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

Row sums are {1, 2, 8, 38, 122, 302, 632, 1178, 2018, 3242, 4952,...}.

LINKS

Table of n, a(n) for n=0..65.

FORMULA

T(n,m)= 1 if m=0 or n=m, else n^3-m^3-(n - m)^3 = 3*n*m*(n-m) =3*A157635(n,m).

Row sums: 2+A083374(n), n>0. - R. J. Mathar, Apr 10 2009

EXAMPLE

{1},

{1, 1},

{1, 6, 1},

{1, 18, 18, 1},

{1, 36, 48, 36, 1},

{1, 60, 90, 90, 60, 1},

{1, 90, 144, 162, 144, 90, 1},

{1, 126, 210, 252, 252, 210, 126, 1},

{1, 168, 288, 360, 384, 360, 288, 168, 1},

{1, 216, 378, 486, 540, 540, 486, 378, 216, 1},

{1, 270, 480, 630, 720, 750, 720, 630, 480, 270, 1}

MATHEMATICA

t[n_, m_] = If[n*m*(n - m) == 0, 1, n^3 - (m^3 + (n - m)^3)];

Table[Table[t[n, m], {m, 0, n}], {n, 0, 10}];

Flatten[%]

CROSSREFS

A141690

Sequence in context: A157275 A157268 A146959 * A328888 A176125 A168289

Adjacent sequences:  A157629 A157630 A157631 * A157633 A157634 A157635

KEYWORD

nonn,easy,tabl

AUTHOR

Roger L. Bagula, Mar 03 2009

EXTENSIONS

Edited by the Associate Editors of the OEIS, Apr 10 2009

STATUS

approved

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 January 17 09:32 EST 2020. Contains 330949 sequences. (Running on oeis4.)