OFFSET
7,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 7..1000
Wikipedia, Partition of a set
Index entries for linear recurrences with constant coefficients, signature (21,-175,735,-1624,1764,-720).
FORMULA
G.f.: x^7*(720*x^6-122388*x^5+235852*x^4-161681*x^3+50632*x^2-7381*x+406) / Product_{j=1..6} (j*x-1).
From Colin Barker, Jan 04 2018: (Start)
a(n) = 32 + 121*2^(n-7) + 155*3^(n-7) + 5*4^(n-5) + 16*5^(n-7) + 6^(n-7) for n>7.
a(n) = 21*a(n-1) - 175*a(n-2) + 735*a(n-3) - 1624*a(n-4) + 1764*a(n-5) - 720*a(n-6) for n>13.
(End)
MATHEMATICA
LinearRecurrence[{21, -175, 735, -1624, 1764, -720}, {406, 1145, 3627, 12521, 46299, 181265, 745107}, 30] (* Harvey P. Dale, Jun 12 2022 *)
PROG
(PARI) Vec(x^7*(406 - 7381*x + 50632*x^2 - 161681*x^3 + 235852*x^4 - 122388*x^5 + 720*x^6) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)) + O(x^40)) \\ Colin Barker, Jan 04 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Apr 13 2016
STATUS
approved