OFFSET
1,2
LINKS
FORMULA
Except for the initial term, a(n) = A113801(n-1) + 1.
a(n) = 14*n - a(n-1) - 26 (with a(1)=0). - Vincenzo Librandi, Dec 17 2010
From Bruno Berselli, Dec 17 2010: (Start)
G.f.: 2*x^2*(1+6*x)/((1+x)*(1-x)^2).
a(n) = 2*A047274(n) = (14*n - 5*(-1)^n - 19)/2.
a(n) = 2*(A001106(n-1) - Sum_{i=1..n-1} a(i)) for n > 1. (End)
MATHEMATICA
Flatten[{#, #+2}&/@(14 Range[0, 30])] (* Harvey P. Dale, Dec 25 2010 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Nov 14 2008
EXTENSIONS
382 replaced with 380 by R. J. Mathar, Jun 28 2010
STATUS
approved