A240793 - OEIS

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A240793

Number of 2Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4

3, 4, 5, 10, 14, 24, 53, 70, 140, 237, 396, 730, 1242, 2166, 3743, 6547, 11397, 19760, 34622, 59868, 104358, 181794, 315863, 550264, 957027, 1665335, 2897587, 5042553, 8774919, 15266419, 26569228, 46226952, 80439383, 139977422, 243558497

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OFFSET

1,1

COMMENTS

Row 2 of A240792

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-2) +4*a(n-3) -a(n-4) -3*a(n-5) -a(n-6) +a(n-7) -9*a(n-8) -9*a(n-9) +8*a(n-10) +15*a(n-11) +4*a(n-12) -15*a(n-13) +2*a(n-14) +3*a(n-15) +7*a(n-16) -7*a(n-17) for n>21

EXAMPLE

Some solutions for n=4

..3..2..3..2....3..2..3..3....3..3..2..3....3..2..3..2....3..2..3..2

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

CROSSREFS

Sequence in context: A191647 A195131 A361666 * A079351 A183050 A176848

Adjacent sequences: A240790 A240791 A240792 * A240794 A240795 A240796

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 12 2014

STATUS

approved