Let M = the 3 X 3 matrix [ 0 1 0 / 0 0 1 / -1, 3*sqrt(3), 3]. M^n * [1 1 1] = [ p q r]; then a(n-1), a(n), a(n+1) = floor p, q, r, respectively.

A094255

Let M = the 3 X 3 matrix [ 0 1 0 / 0 0 1 / -1, 3*sqrt(3), 3]. M^n * [1 1 1] = [ p q r]; then a(n-1), a(n), a(n+1) = floor p, q, r, respectively.

Terms

    a(0) =1a(1) =4a(2) =9a(3) =28a(4) =75a(5) =211a(6) =577a(7) =1591a(8) =4367a(9) =12004a(10) =32975a(11) =90607a(12) =248931a(13) =683946a(14) =1879112a(15) =5162835a(16) =14184754a(17) =38972316a(18) =107075529a(19) =294187633a(20) =808273837a(21) =2220714167a(22) =6101361970a(23) =16763354312a(24) =46056937364a(25) =126540395519

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