OFFSET
0,3
COMMENTS
Number of partitions of n into parts 1, 2, 3, and 6. - Joerg Arndt, Jul 04 2013
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,1,0,-1,-1,2,-1,-1,0,1,1,-1).
FORMULA
a(n) = floor(1/18*(-3*floor((n + 2)/3) + 3*floor(n/3) + 2)*(floor(n/3) + 1) + 1/432*(n + 6)*(2*n^2 + 24*n + 47+9*(-1)^n) + 7/36). - Tani Akinari, Jul 04 2013
MATHEMATICA
CoefficientList[Series[1/((1 - x) (1 - x^2) (1 - x^3) (1 - x^6)), {x, 0, 80}], x] (* Vincenzo Librandi, May 12 2015 *)
PROG
(PARI) Vec(1/((1-x)*(1-x^2)*(1-x^3)*(1-x^6))+O(x^99)) \\ Charles R Greathouse IV, Sep 27 2012
(Magma) [Floor(1/18*(-3*Floor((n + 2)/3) + 3*Floor(n/3) + 2)*(Floor(n/3) + 1) + 1/432*(n + 6)*(2*n^2 + 24*n + 47+9*(-1)^n) + 7/36): n in [0..80]]; // Vincenzo Librandi, May 12 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, May 12 2015
STATUS
approved