OFFSET
0,2
COMMENTS
Row sums of triangle in A112555. - Philippe Deléham, Sep 21 2009
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (-1,2).
FORMULA
Binomial transform of A084246.
a(n) = A077925(n-1) + 1.
a(n) = (4 - (-2)^n)/3.
G.f.: (1+3*x)/((1-x)*(1+2*x)).
E.g.f.: (4*exp(x) - exp(-2*x))/3.
a(n) = -2*a(n-1) + 4 . - Philippe Deléham, Sep 15 2009
a(n+1) = 2*A151575(n). - Philippe Deléham, Sep 21 2009
MATHEMATICA
LinearRecurrence[{-1, 2}, {1, 2}, 40] (* Harvey P. Dale, Nov 05 2016 *)
PROG
(Magma) [(4-(-2)^n)/3: n in [0..40]]; // Vincenzo Librandi, Aug 13 2011
(PARI) Vec((1+3*x)/((1-x)*(1+2*x)) + O(x^40)) \\ Michel Marcus, Feb 25 2016
(SageMath) [(4-(-2)^n)/3 for n in range(41)] # G. C. Greubel, Apr 24 2023
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Paul Barry, May 23 2003
STATUS
approved