Number of nX7 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, rows lexicographically nondecreasing, and columns lexicographically nonincreasing.
A229427
Number of nX7 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, rows lexicographically nondecreasing, and columns lexicographically nonincreasing.
Terms
- a(0) =30a(1) =282a(2) =2187a(3) =13345a(4) =66503a(5) =281016a(6) =1037193a(7) =3420692a(8) =10260128a(9) =28379127a(10) =73192023a(11) =177601008a(12) =408454945a(13) =895812869a(14) =1883191437a(15) =3811219431a(16) =7453126082a(17) =14128822736a(18) =26035706883a(19) =46749593643a(20) =81969420795a(21) =140605855270
External references
- oeis: A229427