OFFSET
1,1
COMMENTS
First bisection of A133146.
Also first bisection of A271713. - Bruno Berselli, Mar 19 2021
LINKS
FORMULA
a(n) = A133146(2*n-2) = (n - 2)^2 + (n - 1)*(n + 1) + n^2.
First differences: a(n+1) - a(n) = A016969(n-1).
G.f.: x*(2 + x + 3*x^2) / (1 - x)^3. - R. J. Mathar, Oct 15 2008
a(n) = 6*n + a(n-1) - 7 for n>1, a(1)=2. - Vincenzo Librandi, Nov 25 2010
MATHEMATICA
Table[3 n^2 - 4 n + 3, {n, 50}] (* Harvey P. Dale, Oct 28 2012 *)
PROG
(PARI) a(n)=3*n^2-4*n+3 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
nonn,less,easy
AUTHOR
Paul Curtz, Aug 28 2008
EXTENSIONS
Edited and extended by R. J. Mathar, Oct 15 2008
STATUS
approved