OFFSET
1,1
COMMENTS
Vertical cylinder: a chessboard where it is supposed that the columns 1 and 6 are in contact (number of columns = 6, number of rows = 2n).
LINKS
Ray Chandler, Table of n, a(n) for n = 1..3305
V. Kotesovec, Non-attacking chess pieces
Index entries for linear recurrences with constant coefficients, signature (6,-13,12,-4).
FORMULA
Recurrence: a(n) = -4*a(n-4) + 12*a(n-3) - 13*a(n-2) + 6*a(n-1).
G.f.: (1+10*x+7*x^2)/((x-1)^2*(2*x-1)^2).
a(n) = (31*n - 65)*2^n + 18*n + 66.
MATHEMATICA
LinearRecurrence[{6, -13, 12, -4}, {16, 90, 344, 1082}, 30] (* Harvey P. Dale, Nov 15 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Sep 21 2011
STATUS
approved