OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (1,1,0,0,-2,0,0,1,1,-1).
FORMULA
G.f.: x*(x^8+14*x^7+38*x^6+67*x^5+80*x^4+74*x^3+46*x^2+20*x+3) / ((x-1)^4*(x+1)^2*(x^2+1)*(x^2+x+1)).
EXAMPLE
For n=1 the 3 partitions of 7*1 = 7 are [1,1,1,4], [1,1,2,3] and [1,2,2,2].
PROG
(PARI)
concat(0, vector(40, n, k=0; forpart(p=7*n, k++, , [4, 4]); k))
(PARI)
concat(0, Vec(x*(x^8+14*x^7+38*x^6+67*x^5+80*x^4+74*x^3+46*x^2+20*x+3) / ((x-1)^4*(x+1)^2*(x^2+1)*(x^2+x+1)) + O(x^100)))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Mar 25 2015
STATUS
approved