OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,1,-1).
FORMULA
a(n) = 10*n - a(n-1) - 8, with n>1, a(1)=6.
From R. J. Mathar, Jan 04 2011: (Start)
a(n) = 2*A168283(n).
a(n+1) = A017341(floor(n/2)).
G.f.: 2*x*(3 + 2*x^2) / ( (1+x)*(x-1)^2 ). (End)
a(n) = a(n-1) + a(n-2) - a(n-3) for n>3. - Vincenzo Librandi, Sep 19 2013
From G. C. Greubel, Jul 23 2016: (Start)
a(n) = (10*n - 5*(-1)^n - 3)/2.
E.g.f.: (1/2)*(-5 + 8*exp(x) + (10*x - 3)*exp(2*x))*exp(-x). (End)
a(n) = a(n-2) + 10 for n>2. - Wesley Ivan Hurt, Jul 24 2016
MAPLE
MATHEMATICA
RecurrenceTable[{a[1]==6, a[n]==10n-a[n-1]-8}, a, {n, 80}] (* or *) LinearRecurrence[{1, 1, -1}, {6, 6, 16}, 80] (* Harvey P. Dale, Apr 25 2011 *)
Table[6 + 10 Floor[(n - 1)/2], {n, 70}] (* or *) CoefficientList[Series[2 (3 + 2 x^2)/((1 + x) (x - 1)^2), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 19 2013 *)
PROG
(Magma) [6+10*Floor((n-1)/2): n in [1..70]]; // Vincenzo Librandi, Sep 19 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Nov 26 2009
EXTENSIONS
New definition by Vincenzo Librandi, Sep 19 2013
STATUS
approved