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A146126 Number of n X n arrays of squares of integers with every (n-2) X (n-2) subblock summing to 5 and every element equal to at least one neighbor. 1
0, 235, 9716, 43201, 125064, 290427, 583948, 1060251, 1783944, 2829619, 4281852, 6235203, 8794216, 12073419, 16197324, 21300427, 27527208, 35032131, 43979644, 54544179, 66910152 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

LINKS

Table of n, a(n) for n=4..24.

FORMULA

Empirical (for n>=8): a(n) = 416*n^4 - 6704*n^3 + 42495*n^2 - 127724*n + 155688. - Vaclav Kotesovec, Nov 30 2012

Conjectures from Colin Barker, Mar 23 2018: (Start)

G.f.: x^5*(235 + 8541*x - 3029*x^2 + 3869*x^3 + 1132*x^4 - 1212*x^5 + 430*x^6 + 18*x^7) / (1 - x)^5.

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>12.

(End)

CROSSREFS

Sequence in context: A257310 A268890 A254676 * A264325 A244007 A218054

Adjacent sequences:  A146123 A146124 A146125 * A146127 A146128 A146129

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 14 2009

STATUS

approved

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Last modified November 27 12:03 EST 2021. Contains 349394 sequences. (Running on oeis4.)