login
A264219
Number of (2+1) X (n+1) arrays of permutations of 0..n*3+2 with each element having directed index change 0,0 0,1 1,0 -1,0 or 0,-2.
1
9, 96, 623, 3736, 24908, 163505, 1056337, 6877345, 44814952, 291509085, 1896866692, 12346072740, 80344855605, 522859320079, 3402709450301, 22144272437752, 144110748923323, 937848095118780, 6103354462609448
OFFSET
1,1
COMMENTS
Row 2 of A264217.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) +9*a(n-2) +71*a(n-3) -72*a(n-4) -322*a(n-5) -1444*a(n-6) +153*a(n-7) +3455*a(n-8) +12675*a(n-9) +3036*a(n-10) -17137*a(n-11) -55432*a(n-12) -19140*a(n-13) +47212*a(n-14) +142351*a(n-15) +56632*a(n-16) -72473*a(n-17) -234679*a(n-18) -101678*a(n-19) +51268*a(n-20) +256960*a(n-21) +115556*a(n-22) +9416*a(n-23) -187054*a(n-24) -78462*a(n-25) -43548*a(n-26) +91648*a(n-27) +28751*a(n-28) +30884*a(n-29) -32369*a(n-30) -5311*a(n-31) -11104*a(n-32) +8112*a(n-33) -444*a(n-34) +1819*a(n-35) -1887*a(n-36) +357*a(n-37) -94*a(n-38) +455*a(n-39) +60*a(n-41) -50*a(n-42) +5*a(n-43) -12*a(n-44) +a(n-45) -a(n-46).
EXAMPLE
Some solutions for n=4
..0..1..2..3..4....5..6..1..3..4....5..1..4..3..9....5..3..1..2..9
.10..8..6.13..9....0..8..2.13.14....0..6..2.13..8....0..8..6.13..4
..5.11..7.12.14...10.11..7.12..9...10.11..7.12.14...10.11..7.12.14
CROSSREFS
Cf. A264217.
Sequence in context: A197665 A064504 A090448 * A005545 A228007 A073560
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 08 2015
STATUS
approved