A250414 Number of length n+1 0..3 arrays with the sum of the minimum of each adjacent pair multiplied by some arrangement of +-1 equal to zero.

7, 36, 99, 476, 1693, 7504, 29221, 123242, 492076, 2021436, 8111306, 32877666, 131905733, 531080990, 2128576994, 8541648896, 34206851593, 137042168870, 548526597108, 2195788650322, 8786230110165, 35158099104398, 140658315422311

Offset: 1

Author

R. H. Hardin, Nov 22 2014

Keywords

• nonn

Comments

Column 3 of A250419

Examples

			Some solutions for n=6
..2....2....1....3....2....3....2....3....0....1....3....0....1....2....0....1
..1....0....3....2....1....0....3....2....1....1....2....0....2....2....2....1
..3....2....3....0....1....1....1....3....3....3....0....1....3....0....1....1
..1....0....0....0....3....0....3....3....1....1....0....3....2....1....2....2
..0....2....2....0....2....0....0....3....1....1....3....1....1....2....2....0
..1....0....1....2....3....0....3....2....2....0....1....0....2....1....3....1
..2....3....1....2....1....1....0....0....2....0....3....3....1....0....2....2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 12*a(n-1) -23*a(n-2) -252*a(n-3) +1056*a(n-4) +1766*a(n-5) -14214*a(n-6) -1040*a(n-7) +103693*a(n-8) -58064*a(n-9) -484016*a(n-10) +411280*a(n-11) +1566651*a(n-12) -1472256*a(n-13) -3670072*a(n-14) +3223960*a(n-15) +6306524*a(n-16) -4463544*a(n-17) -7823016*a(n-18) +3799616*a(n-19) +6723120*a(n-20) -1817056*a(n-21) -3791856*a(n-22) +352032*a(n-23) +1315312*a(n-24) +57408*a(n-25) -252160*a(n-26) -37120*a(n-27) +20352*a(n-28) +4608*a(n-29)