A018839 Squares on infinite chessboard at n moves from center using a {2,3} fairy knight.

1, 8, 32, 88, 192, 304, 372, 416, 472, 540, 608, 676, 744, 812, 880, 948, 1016, 1084, 1152, 1220, 1288, 1356, 1424, 1492, 1560, 1628, 1696, 1764, 1832, 1900, 1968, 2036, 2104, 2172, 2240, 2308, 2376, 2444, 2512, 2580, 2648, 2716, 2784, 2852, 2920, 2988

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

For n >= 8, a(n) = 68n - 72. - David W. Wilson

G.f.: (x+1)*(12*x^8 - 24*x^6 - 20*x^5 + 28*x^4 + 20*x^3 + 12*x^2 + 5*x + 1)/(x-1)^2. - Colin Barker, Oct 04 2012

Mathematica

CoefficientList[Series[(x + 1) (12 x^8 - 24 x^6 - 20 x^5 + 28 x^4 + 20 x^3 + 12 x^2 + 5*x + 1)/(x - 1)^2, {x, 0, 50}], x] (* Vincenzo Librandi, Oct 16 2013 *)

Crossrefs

Cf. A297740 (partial sums).

Sequence in context: A130809 A333174 A372981 * A008412 A014819 A033155

Adjacent sequences: A018836 A018837 A018838 * A018840 A018841 A018842

Keyword

nonn,easy

Author

Marc LeBrun

Status

approved