OFFSET
0,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = A003215(n)*6.
a(n) = a(n-1) + 36*n (with a(0)=6). - Vincenzo Librandi, Nov 30 2010
a(n) = 3*a(n-1)-3*a(n-2)+a(n-3) with a(0)=6, a(1)=42, a(2)=114. - Harvey P. Dale, Dec 16 2012
From G. C. Greubel, Sep 07 2017: (Start)
G.f.: 6*(1 + 4*x + x^2)/(1 - x)^3.
E.g.f.: 6*(1 + 6*x + 3*x^2)*exp(x). (End)
MATHEMATICA
Table[18n(n+1)+6, {n, 0, 40}] (* or *) LinearRecurrence[{3, -3, 1}, {6, 42, 114}, 40] (* Harvey P. Dale, Dec 16 2012 *)
PROG
(PARI) a(n)=18*n*(n+1)+6 \\ Charles R Greathouse IV, Jul 17 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Omar E. Pol, Nov 07 2009
STATUS
approved