OFFSET
0,2
LINKS
Robert Israel, Table of n, a(n) for n = 0..10000
Reticular Chemistry Structure Resource (RCSR), The bew tiling (or net)
Index entries for linear recurrences with constant coefficients, signature (2, 0, -2, 1).
FORMULA
From Robert Israel, Dec 22 2017: (Start)
a(n) = 2*n^2 + 2*n - (-1)^n for n >= 1.
G.f.: (1+3*x+x^2+5*x^3-2*x^4)/((1+x)*(1-x)^3). (End)
MAPLE
1, seq(2*n^2 + 2*n - (-1)^n, n=1..100); # Robert Israel, Dec 22 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 22 2017
STATUS
approved