A223977 Number of 4Xn 0..2 arrays with rows and antidiagonals unimodal.

81, 6561, 186004, 2558848, 22935921, 153196498, 822895397, 3731866676, 14772553616, 52279545002, 168389072033, 500454038667, 1387317570171, 3618413260028, 8942729611918, 21066089007345, 47533740360251

Offset: 1

Author

R. H. Hardin Mar 30 2013

Keywords

• nonn

Comments

Row 4 of A223975

Examples

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

Links

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

Formula

Empirical: a(n) = (456419/5230697472000)*n^16 + (35741/12108096000)*n^15 + (4696759/65383718400)*n^14 + (1960073/1779148800)*n^13 + (31966559/2612736000)*n^12 + (461185847/4790016000)*n^11 + (496257731/914457600)*n^10 + (445395499/203212800)*n^9 + (228272848649/36578304000)*n^8 + (5589292243/435456000)*n^7 + (282633985/14370048)*n^6 + (3122820053/239500800)*n^5 - (91030209653/108972864000)*n^4 - (327561926401/4540536000)*n^3 + (185306939/3439800)*n^2 + (13865993/360360)*n + 7