OFFSET
0,2
MAPLE
a[0]:=1: a[1]:=2: for n from 2 to 30 do if n mod 2 = 0 then a[n]:=3*a[n-1] else a[n]:=3*a[n-1]-2*a[(n-3)/2] fi od: seq(a[n], n=0..30); # Emeric Deutsch, May 22 2007
MATHEMATICA
a[0] = 1; a[1] = 2; a[n_] := If[OddQ@n, 3 a[n - 1] - 2 a[(n - 3)/2], 3 a[n - 1]]; Table[ a[n], {n, 0, 26}] (* Robert G. Wilson v *)
PROG
(PARI) {m=26; v=vector(m+1); v[1]=1; v[2]=2; for(n=2, m, k=3*v[n]; if(n%2==1, k=k-2*v[(n-1)/2]); v[n+1]=k); print(v)} /* Klaus Brockhaus, May 20 2007 */
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul Curtz, May 16 2007
EXTENSIONS
STATUS
approved