A223877 Number of 3Xn 0..3 arrays with rows, diagonals and antidiagonals unimodal

64, 4096, 99223, 1336985, 12520369, 90648289, 539511985, 2744980059, 12266400036, 49108723398, 178849231722, 599732197006, 1869990523340, 5465951755716, 15079975128525, 39496585750239, 98695673406660

Offset

1,1

Comments

Row 3 of A223876

Links

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

Formula

Empirical: a(n) = (89/169374965760)*n^18 + (838301/44460928512000)*n^17 + (1621091/3487131648000)*n^16 + (1400869/186810624000)*n^15 + (17909/188697600)*n^14 + (173367409/186810624000)*n^13 + (137278391/19160064000)*n^12 + (407205871/8382528000)*n^11 + (181325017/812851200)*n^10 + (3123945389/2612736000)*n^9 + (24186912011/12773376000)*n^8 + (223345835639/14370048000)*n^7 - (117158072963/4151347200)*n^6 + (56268858807829/326918592000)*n^5 - (9869157660331/19813248000)*n^4 + (26939359241/20270250)*n^3 - (1768948870159/735134400)*n^2 + (1057606733/408408)*n - 1275 for n>1

Example

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

Crossrefs

Sequence in context: A189193 A188878 A189114 * A188907 A189108 A223802

Adjacent sequences: A223874 A223875 A223876 * A223878 A223879 A223880

Keyword

nonn

Author

R. H. Hardin Mar 28 2013

Status

approved