cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A250428 Number of (n+1)X(4+1) 0..1 arrays with nondecreasing sum of every two consecutive values in every row and column.

Original entry on oeis.org

144, 720, 3600, 12000, 40000, 105000, 275625, 617400, 1382976, 2765952, 5531904, 10160640, 18662400, 32076000, 55130625, 89842500, 146410000, 228399600, 356303376, 535927392, 806105664, 1175570760, 1714374025, 2434614000
Offset: 1

Views

Author

R. H. Hardin, Nov 22 2014

Keywords

Comments

Column 4 of A250432

Examples

			Some solutions for n=6
..0..0..0..1..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0
..0..0..0..0..1....0..0..0..1..0....0..1..0..1..1....0..0..0..1..1
..0..0..1..1..1....0..0..0..1..0....0..0..0..0..0....0..0..1..0..1
..0..1..0..1..1....0..0..0..1..1....1..1..1..1..1....0..1..0..1..1
..1..0..1..1..1....0..1..0..1..1....0..0..1..0..1....1..0..1..0..1
..1..1..1..1..1....0..0..0..1..1....1..1..1..1..1....0..1..1..1..1
..1..1..1..1..1....0..1..0..1..1....0..0..1..1..1....1..0..1..1..1
		

Formula

Empirical: a(n) = 2*a(n-1) +8*a(n-2) -18*a(n-3) -27*a(n-4) +72*a(n-5) +48*a(n-6) -168*a(n-7) -42*a(n-8) +252*a(n-9) -252*a(n-11) +42*a(n-12) +168*a(n-13) -48*a(n-14) -72*a(n-15) +27*a(n-16) +18*a(n-17) -8*a(n-18) -2*a(n-19) +a(n-20)
Empirical for n mod 2 = 0: a(n) = (1/147456)*n^10 + (23/73728)*n^9 + (13/2048)*n^8 + (77/1024)*n^7 + (1763/3072)*n^6 + (4525/1536)*n^5 + (5927/576)*n^4 + (3473/144)*n^3 + (145/4)*n^2 + (63/2)*n + 12
Empirical for n mod 2 = 1: a(n) = (1/147456)*n^10 + (23/73728)*n^9 + (941/147456)*n^8 + (1409/18432)*n^7 + (43777/73728)*n^6 + (115189/36864)*n^5 + (831857/73728)*n^4 + (169595/6144)*n^3 + (717525/16384)*n^2 + (333375/8192)*n + (275625/16384).
a(n+1)=A202095(n). - R. J. Mathar, Dec 04 2014