A139459 - OEIS

A139459

Triangle read by rows: binomial(3*n,3*k), 0 <= k <= n.

1, 1, 1, 1, 20, 1, 1, 84, 84, 1, 1, 220, 924, 220, 1, 1, 455, 5005, 5005, 455, 1, 1, 816, 18564, 48620, 18564, 816, 1, 1, 1330, 54264, 293930, 293930, 54264, 1330, 1

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OFFSET

0,5

COMMENTS

ConvOffsStoT transform of the dodecahedral numbers A006566 starting (1, 20, 84, 220,...)

Row sums give A007613.

The matrix inverse starts:

-1,1;

19,-20,1;

-1513,1596,-84,1;

315523,-332860,17556,-220,1;

-136085041,143562965,-7572565,95095,-455,1;

105261234643,-111045393456,5857368972,-73562060,352716,-816,1; - R. J. Mathar, Mar 22 2013

LINKS

Table of n, a(n) for n=0..35.

EXAMPLE

First few rows of the triangle are:

[0] 1;

[1] 1, 1;

[2] 1, 20, 1;

[3] 1, 84, 84, 1;

[4] 1, 220, 924, 220, 1;

[5] 1, 455, 5005, 5005, 455, 1;

[6] 1, 816, 18564, 48620, 18564, 816, 1;

...

Row 5 = (1, 220, 924, 220, 1) = ConvOffs transform of (1, 20, 84, 220); where A006566 = (0, 1, 20, 84, 220, 455,...).

CROSSREFS

Cf. A006566, A007613, A086645, A034839, A070775, A177808.

Sequence in context: A040402 A040401 A040400 * A154652 A155516 A174674

Adjacent sequences: A139456 A139457 A139458 * A139460 A139461 A139462

KEYWORD

nonn,easy,tabl

AUTHOR

Gary W. Adamson, Apr 22 2008

STATUS

approved