OFFSET
1,2
COMMENTS
Best results found in Al Zimmermann's Programming Contest "Delacorte Numbers". For more information see A261176. All terms beyond a(5) are conjectured based on numerical results. Terms up to a(11) have at least 5 independent verifications. Lower bounds for the next terms are a(14)>=5189492, a(15)>=8110781, a(16)>=12239616, a(17)>=18073562, a(18)>=26055061, a(19)>=36769303, a(20)>=51095165.
LINKS
Al Zimmermann's Programming Contests, Delacorte Numbers, Description, October 2014.
Al Zimmermann's Programming Contests, Delacorte Numbers, Final Report, January 2015.
EXAMPLE
a(3)=180, because no arrangement of the matrix elements exists that produces a larger Delacorte Number than e.g. ((2 3 4)(9 1 5)(8 7 6)).
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Hugo Pfoertner, Aug 15 2015
EXTENSIONS
Lower bounds for a(18) and a(20) improved by Hugo Pfoertner, Nov 22 2015
STATUS
approved