login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A252421
Number of (n+2)X(6+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 2 5 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 2 5 6 or 7
1
3719, 7186, 30724, 62288, 365974, 1757580, 3582225, 21882869, 107926383, 220463165, 1375056342, 6880842955, 14073466867, 88795680194, 447871169161, 916696939171, 5820110209906, 29480626550553, 60364093961967
OFFSET
1,1
COMMENTS
Column 6 of A252423
LINKS
FORMULA
Empirical: a(n) = 135*a(n-3) -6200*a(n-6) +129658*a(n-9) -1479172*a(n-12) +10122008*a(n-15) -43818900*a(n-18) +123860492*a(n-21) -233367460*a(n-24) +297742037*a(n-27) -261058827*a(n-30) +159867108*a(n-33) -69122310*a(n-36) +20695032*a(n-39) -3955984*a(n-42) +409280*a(n-45) -16896*a(n-48) for n>56
EXAMPLE
Some solutions for n=4
..0..3..1..0..0..1..0..0....1..1..2..1..1..2..1..1....1..1..2..1..1..2..1..1
..0..0..1..3..0..1..0..0....3..0..1..0..0..1..3..0....3..0..1..0..0..1..0..3
..1..1..2..1..1..2..1..1....0..0..1..0..3..1..0..0....0..0..1..0..0..1..0..0
..0..0..1..0..0..1..0..0....1..1..2..1..1..2..1..1....1..1..2..1..1..2..1..1
..3..0..1..0..0..1..3..0....3..0..1..0..0..1..0..3....0..0..1..0..0..1..0..0
..1..1..2..1..1..2..1..1....0..0..1..0..0..1..0..0....3..0..1..3..0..1..0..0
CROSSREFS
Sequence in context: A252161 A180396 A158917 * A296908 A237736 A289512
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 17 2014
STATUS
approved