A201084 - OEIS

%I #5 Mar 31 2012 12:36:42

%S 9,61,323,1759,9593,52401,286207,1563111,8536807,46623423,254632457,

%T 1390667451,7595086541,41480325457,226543492197,1237260160029,

%U 6757257460559,36904549131343,201553034567103,1100775560224471

%N Number of -4..4 arrays of n elements with first and second differences also in -4..4

%C Column 4 of A201088

%H R. H. Hardin, <a href="/A201084/b201084.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) -2*a(n-2) -9*a(n-3) +27*a(n-4) -25*a(n-5) -48*a(n-6) +46*a(n-7) -7*a(n-8) -47*a(n-9) +49*a(n-10) +54*a(n-11) -16*a(n-12) -21*a(n-13) +10*a(n-14) +21*a(n-15) +9*a(n-16) -11*a(n-17) -9*a(n-18) +2*a(n-19) +3*a(n-20) -5*a(n-22) -3*a(n-23) +2*a(n-24) -a(n-26)

%e Some solutions for n=6

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Nov 26 2011