OFFSET
0,3
LINKS
A. Goupil, M.-E. Pellerin and J. de Wouters d'oplinter, Snake Polyominoes, arXiv preprint arXiv:1307.8432, 2013
Index entries for linear recurrences with constant coefficients, signature (4,-3,4,-4).
MATHEMATICA
a[0] = a[1] = 1; a[2] = 3; a[3] = 13; a[4] = 45; a[n_] := a[n] = 3*a[n-1] + 4*a[n-3] + 6; Array[a, 30, 0] (* Jean-François Alcover, Sep 21 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 23 2013
STATUS
approved