A223871 Number of n X 3 0..3 arrays with rows, diagonals and antidiagonals unimodal.

50, 2500, 99223, 3863372, 152918517, 6066668157, 240345697904, 9519219712534, 377068749332794, 14936662560715369, 591673197324653702, 23437360043162717039, 928401612451857089159, 36775894520547706164712

Offset: 1

Author

R. H. Hardin, Mar 28 2013

Keywords

• nonn

Comments

Column 3 of A223876.

Examples

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

Links

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

Crossrefs

Cf. A223876.

Formula

Empirical: a(n) = 40*a(n-1) -132*a(n-2) +4459*a(n-3) +13745*a(n-4) -279374*a(n-5) -216409*a(n-6) -10116301*a(n-7) -38256907*a(n-8) [phone]*a(n-9) [phone]*a(n-10) [phone]*a(n-11) [phone]*a(n-12) -40103358672*a(n-13) -213466075938*a(n-14) -190360919826*a(n-15) -232629523048*a(n-16) [phone]*a(n-17) [phone]*a(n-18) [phone]*a(n-19) [phone]*a(n-20) [phone]*a(n-21) -1858101760192*a(n-22) -2045017763520*a(n-23) -1010972140800*a(n-24) -530550835200*a(n-25) [phone]*a(n-26) [phone]*a(n-27) [phone]*a(n-28).