The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A189807 Number of right triangles on an (n+1) X 3 grid. 1
 14, 44, 94, 158, 238, 330, 434, 550, 678, 818, 970, 1134, 1310, 1498, 1698, 1910, 2134, 2370, 2618, 2878, 3150, 3434, 3730, 4038, 4358, 4690, 5034, 5390, 5758, 6138, 6530, 6934, 7350, 7778, 8218, 8670, 9134, 9610, 10098, 10598, 11110, 11634, 12170, 12718 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 2 of A189814. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 6*n^2 + 26*n - 42 for n>3. Conjectures from Colin Barker, May 03 2018: (Start) G.f.: 2*x*(7 + x + 2*x^2 - 3*x^3 + x^4 - 2*x^5) / (1 - x)^3. a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>6. (End) EXAMPLE Some solutions for n=3: ..3..0....0..1....2..1....1..1....2..0....3..0....1..1....2..2....0..0....3..1 ..0..0....0..0....1..0....0..1....2..1....2..0....0..2....1..1....0..2....1..1 ..3..1....3..1....3..0....1..2....3..0....3..2....2..2....3..1....3..0....3..2 CROSSREFS Cf. A189814. Sequence in context: A089031 A265152 A033587 * A009942 A031130 A215199 Adjacent sequences: A189804 A189805 A189806 * A189808 A189809 A189810 KEYWORD nonn AUTHOR R. H. Hardin, Apr 28 2011 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 May 25 02:39 EDT 2024. Contains 372782 sequences. (Running on oeis4.)