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A252508 Number of (n+2)X(2+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 2 5 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 0 2 5 6 or 7 1
1515, 1644, 3980, 9277, 25197, 76113, 231372, 698936, 2121821, 6483996, 19881260, 61024374, 187473423, 576442523, 1773336035, 5457204006, 16797726720, 51712080105, 159214729408, 490238324306, 1509560349792, 4648472850677 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A252514

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 2*a(n-1) +2*a(n-2) +28*a(n-3) -46*a(n-4) -50*a(n-5) -302*a(n-6) +339*a(n-7) +444*a(n-8) +1659*a(n-9) -708*a(n-10) -1726*a(n-11) -5313*a(n-12) -1724*a(n-13) +2968*a(n-14) +10952*a(n-15) +9601*a(n-16) -1890*a(n-17) -15584*a(n-18) -17207*a(n-19) -452*a(n-20) +16151*a(n-21) +18538*a(n-22) +1742*a(n-23) -12916*a(n-24) -15168*a(n-25) -2082*a(n-26) +8130*a(n-27) +9975*a(n-28) +1924*a(n-29) -3684*a(n-30) -4042*a(n-31) -880*a(n-32) +880*a(n-33) +440*a(n-34) for n>41

EXAMPLE

Some solutions for n=4

..2..3..1..2....3..2..2..1....3..1..3..2....1..3..1..1....3..1..2..2

..3..1..3..2....1..3..1..3....2..3..1..3....3..2..0..3....1..3..1..3

..1..3..1..2....3..1..3..1....2..1..3..1....1..0..1..1....3..1..3..2

..3..1..3..1....1..3..1..2....2..3..1..3....1..0..1..1....1..3..1..2

..2..3..1..3....3..1..3..2....2..1..3..1....0..2..0..3....3..1..3..1

..2..1..2..2....2..3..1..3....2..3..1..2....1..3..1..3....2..3..2..2

CROSSREFS

Sequence in context: A317477 A064584 A318713 * A031810 A020415 A257753

Adjacent sequences:  A252505 A252506 A252507 * A252509 A252510 A252511

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 18 2014

STATUS

approved

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Last modified December 2 16:17 EST 2021. Contains 349445 sequences. (Running on oeis4.)