OFFSET
1,1
COMMENTS
Column 4 of A217028
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 138*a(n-1) -1763*a(n-2) -104096*a(n-3) +1809621*a(n-4) +15350519*a(n-5) -373958850*a(n-6) +742781203*a(n-7) +16974636444*a(n-8) -83414425341*a(n-9) -243838748413*a(n-10) +2303032008546*a(n-11) -642413643539*a(n-12) -27716237446800*a(n-13) +49075197330378*a(n-14) +144241631926804*a(n-15) -470008841261549*a(n-16) -140883178920985*a(n-17) +1769208519222178*a(n-18) -1130914844768352*a(n-19) -2544187846139448*a(n-20) +2892545854908279*a(n-21) +1630408747385312*a(n-22) -3021516801742966*a(n-23) -330376708494636*a(n-24) +1740628750155765*a(n-25) -171078581715509*a(n-26) -603090654119312*a(n-27) +132828725931224*a(n-28) +127444286159131*a(n-29) -39514256602536*a(n-30) -15636690313044*a(n-31) +6313677455724*a(n-32) +919389460803*a(n-33) -546250997674*a(n-34) -1662750703*a(n-35) +22252053530*a(n-36) -2029538078*a(n-37) -254802637*a(n-38) +44411642*a(n-39) -183141*a(n-40) -297102*a(n-41) +14334*a(n-42) +448*a(n-43) -49*a(n-44) +a(n-45)
EXAMPLE
Some solutions for n=3 (movement: 0=n 1=e 2=s 3=w)
..2..1..3..3....1..3..2..3....1..2..1..2....2..2..1..3....1..3..2..3
..1..1..1..3....0..0..2..3....0..0..1..2....0..2..0..0....0..2..0..3
..1..0..3..0....0..1..1..0....0..0..1..3....1..3..1..3....0..3..1..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Sep 24 2012
STATUS
approved