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A265956 Number of nX2 integer arrays with each element equal to the number of horizontal, vertical, diagonal and antidiagonal neighbors less than itself. 1

%I #5 Dec 19 2015 07:47:54

%S 3,75,235,4267,72764,527311,7155883,100785131,1027584101,12833963832,

%T 165303275897,1900259926847,23239578482787,288755569082063,

%U 3451652547267892,42017736457914547,515098292139995839

%N Number of nX2 integer arrays with each element equal to the number of horizontal, vertical, diagonal and antidiagonal neighbors less than itself.

%C Column 2 of A265960.

%H R. H. Hardin, <a href="/A265956/b265956.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) +27*a(n-2) +1471*a(n-3) -231*a(n-4) -13234*a(n-5) -596900*a(n-6) -692608*a(n-7) +877376*a(n-8) +76755096*a(n-9) +118908760*a(n-10) -45301392*a(n-11) -3771249872*a(n-12) -6892614656*a(n-13) +3861939840*a(n-14) +54161306496*a(n-15) +87648124672*a(n-16) +51124427264*a(n-17) +144898730496*a(n-18) +211539062784*a(n-19) -328584368128*a(n-20) +94100811776*a(n-21) +1882455728128*a(n-22) +462247297024*a(n-23) -245677588480*a(n-24) +1616868474880*a(n-25) -176088416256*a(n-26) -424648114176*a(n-27) +451207495680*a(n-28) -229735661568*a(n-29) +35087450112*a(n-30)

%e Some solutions for n=4

%e ..1..3....0..1....0..3....0..0....0..1....1..0....0..1....2..1....0..1....3..0

%e ..2..0....3..4....0..0....5..4....3..1....5..4....5..4....0..3....5..4....2..2

%e ..5..4....2..4....5..0....1..2....3..3....0..0....1..0....5..3....0..1....5..0

%e ..1..0....1..0....0..0....3..0....0..0....3..2....1..3....0..0....3..1....1..2

%Y Cf. A265960.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 19 2015

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Last modified June 18 04:26 EDT 2024. Contains 373468 sequences. (Running on oeis4.)