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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A334891 Number of ways to choose 4 points that form an square from the A000292(n) points in a regular tetrahedral grid where each side has n vertices. 0
 0, 0, 3, 12, 36, 84, 174, 336, 612, 1044, 1701 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS a(n) >= 3*A001752(n-2). LINKS EXAMPLE For n = 4, three of the a(4) = 36 squares are (in barycentric coordinates) {(0,2,1,1),(1,1,0,2),(1,1,2,0),(2,0,1,1)}, {(0,0,2,2),(0,2,0,2),(2,0,2,0),(2,2,0,0)}, and {(0,0,1,3),(0,1,0,3),(1,0,1,2),(1,1,0,2)}. The other squares can be derived from these by translations or symmetries of the tetrahedron. CROSSREFS Cf. A000292, A001752. Cf. A334581 (equilateral triangle), A334881 (cubic grid). Sequence in context: A135190 A101069 A225259 * A242526 A167667 A292291 Adjacent sequences:  A334888 A334889 A334890 * A334892 A334893 A334894 KEYWORD nonn,more AUTHOR Peter Kagey, May 14 2020 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.

Last modified June 26 19:53 EDT 2022. Contains 354885 sequences. (Running on oeis4.)