0,5

Greatest numbers in each 2D triangle form A022916 = (multinomial coefficient n!/([n/3]![(n+1)/3]![(n+2)/3]!).

2D triangle sums are powers of 3.

See A046816 for another version.

Table of n, a(n) for n=0..80.

Coefficients of x, y, z in (x+y+z)^n.

.1 3 3 1 ... Here is the third slice of the pyramid

. 3 6 3

.. 3 3

... 1 .....

Cf. A007318, A046816, A002378, A027480, A033487, A033488.

Sequence in context: A035176 A322976 A011793 * A228106 A098199 A309474

Adjacent sequences: A109646 A109647 A109648 * A109650 A109651 A109652

nonn,tabf,easy

Philippe Deléham, Aug 03 2005

approved