A254424 - OEIS

%I #6 Jul 23 2025 14:40:36

%S 2180,26783,423141,6880359,109896298,1753478415,27927013232,

%T 445084441966,7093876225958,113098580382568,1803358896611418,

%U 28758054154692016,458632880805879770,7314638842629672616,116663314851350849442

%N Number of (3+1)X(n+1) 0..2 arrays with every 2X2 subblock diagonal maximum minus antidiagonal maximum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.

%C Row 3 of A254422

%H R. H. Hardin, <a href="/A254424/b254424.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 53*a(n-1) -1052*a(n-2) +8298*a(n-3) +12027*a(n-4) -644699*a(n-5) +3383022*a(n-6) +5821120*a(n-7) -105582868*a(n-8) +183491212*a(n-9) +1149464040*a(n-10) -3940967952*a(n-11) -5526556544*a(n-12) +32505663520*a(n-13) +11662935360*a(n-14) -148192467456*a(n-15) -11627458560*a(n-16) +409352481792*a(n-17) +46624425984*a(n-18) -673695553536*a(n-19) -198304174080*a(n-20) +577600782336*a(n-21) +304474816512*a(n-22) -166164037632*a(n-23) -148487012352*a(n-24) -27518828544*a(n-25) for n>32

%e Some solutions for n=2

%e ..0..1..1....2..2..1....1..2..2....1..2..0....0..0..0....1..2..0....0..2..0

%e ..2..0..0....1..2..0....0..2..0....1..2..2....0..0..0....2..2..2....2..2..0

%e ..2..0..0....2..2..1....1..2..1....1..2..0....1..1..1....0..2..2....2..2..1

%e ..2..1..2....1..1..0....1..2..0....0..2..0....1..0..2....1..2..0....0..0..1

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 30 2015