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A202125 Number of -n..n arrays of 4 elements with first, second and third differences also in -n..n. 2
19, 127, 475, 1279, 2833, 5509, 9739, 16039, 25003, 37279, 53605, 74797, 101719, 135331, 176671, 226819, 286957, 358345, 442279, 540163, 653479, 783739, 932569, 1101673, 1292779, 1507735, 1748467, 2016919, 2315161, 2645341, 3009619, 3410287 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Row 4 of A202124.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) - 3*a(n-2) + 3*a(n-3) - 6*a(n-4) + 6*a(n-5) - 3*a(n-6) + 3*a(n-7) - 3*a(n-8) + a(n-9).
Empirical g.f.: x*(19 + 70*x + 151*x^2 + 178*x^3 + 154*x^4 + 70*x^5 + 19*x^6 - 2*x^7 + x^8) / ((1 - x)^5*(1 + x + x^2)^2). - Colin Barker, Mar 03 2018
EXAMPLE
Some solutions for n=5:
-4 1 0 1 -2 2 3 -3 -2 2 2 1 3 -1 -1 2
-4 -4 -4 -1 -2 0 2 0 -4 2 2 -1 -1 0 -1 4
-1 -5 -4 -2 0 -1 0 4 -2 2 0 0 -3 -2 -1 4
1 -5 1 1 1 0 0 5 1 4 -4 1 0 -5 4 1
CROSSREFS
Cf. A202124.
Sequence in context: A164905 A142106 A078851 * A169727 A338300 A177459
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 11 2011
STATUS
approved

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Last modified July 12 12:19 EDT 2024. Contains 374247 sequences. (Running on oeis4.)