OFFSET
1,1
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (6,-11,6).
FORMULA
a(n) = A001117(n), n>=3. - R. J. Mathar, Jul 20 2010
From Colin Barker, May 21 2017: (Start)
G.f.: 3*x*(1 - 9*x + 31*x^2 - 39*x^3 + 18*x^4) / ((1 - x)*(1 - 2*x)*(1 - 3*x)).
a(n) = 3 - 3*2^n + 3^n for n>2.
a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3) for n>5.
(End)
MAPLE
A179483 := proc(n) add( (-1)^(m+1)*binomial(3, m)*m^n, m=1..n) ; end proc: # R. J. Mathar, Jan 31 2011
MATHEMATICA
Sum[(-1)^(m+1)Binomial[3, m]m^k, {m, 1, k}]
PROG
(PARI) Vec(3*x*(1 - 9*x + 31*x^2 - 39*x^3 + 18*x^4) / ((1 - x)*(1 - 2*x)*(1 - 3*x)) + O(x^30)) \\ Colin Barker, May 21 2017
CROSSREFS
KEYWORD
sign,easy
AUTHOR
M. Lawrence Glasser, Jul 16 2010
STATUS
approved