A253370 Number of (n+1)X(3+1) 0..2 arrays with every 2X2 subblock sum nondecreasing horizontally, vertically and antidiagonally ne-to-sw

2500, 22877, 219438, 1027387, 5829147, 21245477, 92753092, 299160892, 1126530715, 3407488838, 11740231069, 34352248435, 112041051335, 322932426766, 1018089749261, 2922063885711, 9022892348437, 25949732507316, 79139400390836

Offset

1,1

Comments

Column 3 of A253375

Links

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

Formula

Empirical: a(n) = 9*a(n-1) +18*a(n-2) -390*a(n-3) +363*a(n-4) +7557*a(n-5) -16924*a(n-6) -85080*a(n-7) +289038*a(n-8) +592626*a(n-9) -3022596*a(n-10) -2302692*a(n-11) +22010974*a(n-12) +263586*a(n-13) -118108608*a(n-14) +60625464*a(n-15) +480363315*a(n-16) -453795339*a(n-17) -1497838078*a(n-18) +2041953882*a(n-19) +3566209239*a(n-20) -6619257735*a(n-21) -6304597140*a(n-22) +16357594512*a(n-23) +7550240128*a(n-24) -31527338352*a(n-25) -3791317152*a(n-26) +47758481952*a(n-27) -6659648352*a(n-28) -56728278048*a(n-29) +20129722880*a(n-30) +52207707264*a(n-31) -28856183808*a(n-32) -36302235648*a(n-33) +27669476352*a(n-34) +18144427008*a(n-35) -18828638464*a(n-36) -5799153408*a(n-37) +9055982592*a(n-38) +719677440*a(n-39) -2944438272*a(n-40) +244629504*a(n-41) +582598656*a(n-42) -119439360*a(n-43) -53084160*a(n-44) +15925248*a(n-45) for n>48

Example

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

Crossrefs

Sequence in context: A062120 A220025 A253377 * A204225 A251115 A235439

Adjacent sequences: A253367 A253368 A253369 * A253371 A253372 A253373

Keyword

nonn

Author

R. H. Hardin, Dec 30 2014

Status

approved