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A115286
a(n) = (1/6)*(n^6+3*n^4+12*n^3+8*n^2).
1
0, 4, 40, 228, 960, 3200, 8904, 21560, 46848, 93420, 173800, 305404, 511680, 823368, 1279880, 1930800, 2837504, 4074900, 5733288, 7920340, 10763200, 14410704, 19035720, 24837608, 32044800, 40917500, 51750504, 64876140, 80667328, 99540760, 121960200
OFFSET
0,2
REFERENCES
Nick Baxter, The Burnside di-lemma: combinatorics and puzzle symmetry, in Tribute to a Mathemagician, Peters, 2005, pp. 199-210.
FORMULA
From Chai Wah Wu, Jun 05 2016: (Start)
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n > 6.
G.f.: 4*x*(1 + 3*x + 8*x^2 + 16*x^3 + 2*x^4)/(1 - x)^7. (End)
PROG
(Python)
A115286_list, m = [], [120, -300, 272, -96, 8, 0, 0]
for _ in range(1001):
A115286_list.append(m[-1])
for i in range(6):
m[i+1] += m[i] # Chai Wah Wu, Jun 05 2016
CROSSREFS
Sequence in context: A273310 A229088 A270088 * A119635 A367557 A283660
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Apr 11 2006
STATUS
approved