A203863 Number of (n+1)X2 0..4 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) nondecreasing in column and row directions, respectively

205, 1648, 10077, 55848, 280509, 1322098, 5914273, 25415265, 105707437, 428159717, 1696690158, 6602453062, 25304540729, 95747687170, 358387784429, 1329182446188, 4891208234959, 17879134951404, 64982533891604

Offset

1,1

Comments

Column 1 of A203870

Links

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

Formula

Empirical: a(n) = 15*a(n-1) -85*a(n-2) +190*a(n-3) +97*a(n-4) -1217*a(n-5) +1387*a(n-6) +2391*a(n-7) -5633*a(n-8) -1218*a(n-9) +10223*a(n-10) -2553*a(n-11) -10934*a(n-12) +5334*a(n-13) +7509*a(n-14) -4795*a(n-15) -3409*a(n-16) +2544*a(n-17) +1019*a(n-18) -845*a(n-19) -193*a(n-20) +173*a(n-21) +21*a(n-22) -20*a(n-23) -a(n-24) +a(n-25)

Example

Some solutions for n=4
..2..2....1..2....3..1....1..0....4..2....4..1....2..2....1..4....2..3....3..1
..1..3....0..4....0..4....1..2....2..4....1..4....2..2....1..4....2..3....1..3
..2..4....0..4....1..3....2..4....2..4....1..4....0..4....4..1....1..4....4..2
..2..4....2..3....3..1....2..4....3..4....4..4....4..2....1..4....1..4....2..4
..2..4....4..4....0..4....2..4....3..4....4..4....2..4....3..2....1..4....2..4

Crossrefs

Sequence in context: A249703 A015974 A203870 * A203896 A203889 A226564

Adjacent sequences: A203860 A203861 A203862 * A203864 A203865 A203866

Keyword

nonn

Author

R. H. Hardin Jan 07 2012

Status

approved