A223802 Number of 3Xn 0..3 arrays with rows and antidiagonals unimodal.
64, 4096, 110116, 1658703, 16979881, 131295500, 818316500, 4293683039, 19561009057, 79169569680, 289707943960, 971844411710, 3021916484046, 8789182733640, 24090737306249, 62620436201529, 155188103218258
Offset: 1
Keywords
Examples
Some solutions for n=3 ..2..2..0....2..3..3....3..1..0....2..0..0....0..3..1....2..1..0....1..2..2 ..3..1..0....2..2..1....2..1..1....0..0..3....3..2..1....1..3..1....1..2..0 ..1..1..3....1..2..0....3..3..0....1..3..1....2..2..0....1..3..1....3..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = (89/169374965760)*n^18 + (811/30536352000)*n^17 + (94651/130767436800)*n^16 + (32953/2554051500)*n^15 + (353321/2134978560)*n^14 + (42487607/26687232000)*n^13 + (2427919/205286400)*n^12 + (329331899/4790016000)*n^11 + (2304632003/7315660800)*n^10 + (10342060619/9144576000)*n^9 + (4533016361/1437004800)*n^8 + (13748687149/2052864000)*n^7 + (50457321263/4670265600)*n^6 + (22295176297/1796256000)*n^5 + (1377479947/136216080)*n^4 + (30053444821/9081072000)*n^3 + (2978057767/367567200)*n^2 + (16725/2431)*n + 1
Comments