OFFSET
1,2
COMMENTS
Column 4 of A264655.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) +36*a(n-3) -18*a(n-4) +186*a(n-5) +83*a(n-6) +144*a(n-7) +684*a(n-8) -1872*a(n-9) +508*a(n-10) -5048*a(n-11) -3240*a(n-12) +720*a(n-13) -95040*a(n-14) +3072*a(n-15) +3456*a(n-16) +13824*a(n-18) for n>21
EXAMPLE
Some solutions for n=4
..1..2..7..4..9....1..2..3..4..9....1..6..7..4..9....1..2..3..4..9
..6..0.12.13..3...10..0..8.13.14...10.11..8..2..3...10.11..8.13.14
.15.16.17.14..8...15.16..6..7.19...15.12..0.14.19...15.16..0.18.19
.20.10..5.19.24...20.17..5.12.24...20.17..5.23.13...20.17..5..6..7
.21.22.23.11.18...21.22.23.11.18...21.22.16.24.18...21.22.23.24.12
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 20 2015
STATUS
approved