Voozh

A083336

a(n) = 4*a(n-2) - a(n-4).

3, 3, 9, 12, 33, 45, 123, 168, 459, 627, 1713, 2340, 6393, 8733, 23859, 32592, 89043, 121635, 332313, 453948, 1240209, 1694157, 4628523, 6322680, 17273883, 23596563, 64467009, 88063572, 240594153, 328657725, 897909603, 1226567328, 3351044259, 4577611587, 12506267433

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,1

COMMENTS

a(n)/A002531(n+1) converges to sqrt(3).

LINKS

Table of n, a(n) for n=0..34.

Index entries for linear recurrences with constant coefficients, signature (0,4,0,-1).

FORMULA

a(2*n) = A082841(n) = a(2*n-1) + 3*A002531(2*n).

a(2*n+1) = (a(2*n) + 3*A002531(2*n+1)) / 2.

G.f.: (3 + 3*x - 3*x^2) / (1 - 4*x^2 + x^4).