- 3-aliquot tree, a Wedderburn-Etherington number, the
second non-trivial
enneagonal number,
after 24, a
centered triangular number, the
number of parallelogram...
- n-gonal
bipyramid Properties convex,
regular polygon faces, isogonal,
translated bases,
sides ⊥
bases Net Example: net of
uniform enneagonal prism (n = 9)...
- A
nonagonal number, or an
enneagonal number, is a
figurate number that
extends the
concept of
triangular and
square numbers to the
nonagon (a nine-sided...
- A
centered nonagonal number (or
centered enneagonal number) is a
centered figurate number that
represents a
nonagon with a dot in the
center and all other...
- In geometry, an n-gonal
antiprism or n-antiprism is a
polyhedron composed of two
parallel direct copies (not
mirror images) of an n-sided polygon, connected...
- 2016-05-29. "Sloane's A060544 :
Centered 9-gonal (also
known as
nonagonal or
enneagonal) numbers". The On-Line
Encyclopedia of
Integer Sequences. OEIS Foundation...
- In geometry, a bipyramid, dipyramid, or
double pyramid is a
polyhedron formed by
fusing two
pyramids together base-to-base. The
polygonal base of each...
- Foundation. "Sloane's A060544 :
Centered 9-gonal (also
known as
nonagonal or
enneagonal) numbers". The On-Line
Encyclopedia of
Integer Sequences. OEIS Foundation...
- In geometry, an n-gonal trapezohedron, n-trapezohedron, n-antidipyramid, n-antibipyramid, or n-deltohedron, is the dual
polyhedron of an n-gonal antiprism...
-
Problem for n = 6. Sloane, N. J. A. (ed.). "Sequence A001106 (9-gonal (or
enneagonal or nonagonal) numbers)". The On-Line
Encyclopedia of
Integer Sequences...
