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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A334705 Triangle read by rows: T(n,k) (1 <= k <= n) = number of ways to choose three points from an n X k grid of points which are the vertices of a triangle of nonzero area. 7
 0, 0, 4, 0, 18, 76, 0, 48, 200, 516, 0, 100, 412, 1056, 2148, 0, 180, 738, 1884, 3820, 6768, 0, 294, 1200, 3052, 6176, 10922, 17600, 0, 448, 1824, 4628, 9352, 16516, 26588, 40120, 0, 648, 2632, 6668, 13456, 23740, 38192, 57588, 82608, 0, 900, 3650, 9232, 18612, 32812, 52758, 79508, 114000, 157252 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS It follows from the definitions that T(n,k) + A334704(n,k) = A334703(n,k) for 1 <= k <= n. LINKS Table of n, a(n) for n=1..55. EXAMPLE Triangle begins: 0, 0, 4, 0, 18, 76, 0, 48, 200, 516, 0, 100, 412, 1056, 2148, 0, 180, 738, 1884, 3820, 6768, 0, 294, 1200, 3052, 6176, 10922, 17600, 0, 448, 1824, 4628, 9352, 16516, 26588, 40120, 0, 648, 2632, 6668, 13456, 23740, 38192, 57588, 82608, 0, 900, 3650, 9232, 18612, 32812, 52758, 79508, 114000, 157252, 0, 1210, 4900, 12380, 24940, 43934, 70608, 106364, 152456, 210234, 280988, ... This is the lower half of a symmetric array. The full symmetric array begins: 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... 0, 4, 18, 48, 100, 180, 294, 448, 648, 900, 1210, 1584, ... 0, 18, 76, 200, 412, 738, 1200, 1824, 2632, 3650, 4900, 6408, ... 0, 48, 200, 516, 1056, 1884, 3052, 4628, 6668, 9232, 12380, 16176, ... 0, 100, 412, 1056, 2148, 3820, 6176, 9352, 13456, 18612, 24940, 32568, ... 0, 180, 738, 1884, 3820, 6768, 10922, 16516, 23740, 32812, 43934, 57336, ... 0, 294, 1200, 3052, 6176, 10922, 17600, 26588, 38192, 52758, 70608, 92112, ... 0, 448, 1824, 4628, 9352, 16516, 26588, 40120, 57588, 79508, 106364, 138708, ... 0, 648, 2632, 6668, 13456, 23740, 38192, 57588, 82608, 114000, 152456, 198760, ... 0, 900, 3650, 9232, 18612, 32812, 52758, 79508, 114000, 157252, 210234, 274016 , ... 0, 1210, 4900, 12380, 24940, 43934, 70608, 106364, 152456, 210234, 280988, 366152, ... ... CROSSREFS This is a companion to the triangles A334703 and A334704. Rows (or columns) 2,3,4,5 of the full array are A045991, A262402, A296367, A334707. The main diagonal is A045996. Sequence in context: A167350 A215669 A244310 * A156457 A058348 A184946 Adjacent sequences: A334702 A334703 A334704 * A334706 A334707 A334708 KEYWORD nonn,tabl AUTHOR N. J. A. Sloane, Jun 13 2020. EXTENSIONS Rows 6 onwards from Tom Duff (see the Duff link in A334704). - N. J. A. Sloane, Jun 19 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 August 11 10:58 EDT 2024. Contains 375068 sequences. (Running on oeis4.)