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A228222 Number of second differences of arrays of length 7 of numbers in 0..n. 1
127, 2059, 14053, 58141, 176851, 439927, 951049, 1854553, 3342151, 5659651, 9113677, 14078389, 21002203, 30414511, 42932401, 59267377, 80232079, 106747003, 139847221, 180689101, 230557027, 290870119, 363188953, 449222281, 550833751 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..63

FORMULA

Empirical: a(n) = 56*n^5 + 14*n^4 - 108*n^3 + 289*n^2 - 125*n + 1.

Conjectures from Colin Barker, Sep 10 2018: (Start)

G.f.: x*(127 + 1297*x + 3604*x^2 + 2168*x^3 - 475*x^4 - x^5) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.

(End)

EXAMPLE

Some solutions for n=4:

.-7....5...-3....1...-2...-1....1....5...-1....3....6...-6....5....0....5...-1

..2...-1....1...-2....2....0...-1...-6...-1...-1...-3....5....2....1....0....2

..2...-1...-2....5...-2...-2....2....4....6...-1....4....1...-6....3...-5....0

.-2...-1...-1...-7....3....0....0...-6...-8....3...-3...-2....4...-4....5...-5

..4....2....3....5...-2....4....0....4....6...-6...-3...-3....1....1...-1....8

CROSSREFS

Row 5 of A228218.

Sequence in context: A258015 A181126 A228263 * A022523 A090029 A152726

Adjacent sequences:  A228219 A228220 A228221 * A228223 A228224 A228225

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 16 2013

STATUS

approved

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Last modified September 20 22:20 EDT 2019. Contains 327252 sequences. (Running on oeis4.)