A115286 a(n) = (1/6)*(n^6+3*n^4+12*n^3+8*n^2).

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.

Links

Chai Wah Wu, Table of n, a(n) for n = 0..1000

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

Adjacent sequences: A115283 A115284 A115285 * A115287 A115288 A115289

Keyword

nonn

Author

N. J. A. Sloane, Apr 11 2006

Status

approved