OFFSET
1,1
COMMENTS
Vertical cylinder: a chessboard where it is supposed that the columns 1 and 4 are in contact (number of columns = 4, number of rows = 2n).
LINKS
Ray Chandler, Table of n, a(n) for n = 1..3307
V. Kotesovec, Non-attacking chess pieces
Index entries for linear recurrences with constant coefficients, signature (5, -8, 4).
FORMULA
Recurrence: a(n) = 4*a(n-3) - 8*a(n-2) + 5*a(n-1).
G.f.: -(1+3*x)/((x-1)*(2*x-1)^2).
Explicit formula: a(n) = (5*n-3)*2^n + 4.
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Sep 21 2011
STATUS
approved