A008388 Crystal ball sequence for A_6 lattice.

1, 43, 505, 3067, 12559, 39733, 104959, 242845, 507781, 980407, 1775005, 3047815, 5006275, 7919185, 12127795, 18057817, 26232361, 37285795, 51978529, 71212723, 96048919, 127723597, 167667655

Offset

0,2

Comments

Partial sums of A008387.

Links

T. D. Noe, Table of n, a(n) for n = 0..1000

J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (pdf).

Index entries for crystal ball sequences

Index entries for linear recurrences with constant coefficients, signature (7, -21, 35, -35, 21, -7, 1).

Formula

a(n) = 1+7*n*(n+1)*(n^2+n+3)*(11*n^2+11*n+14)/60. - T. D. Noe, Apr 29 2007

G.f.: (1+36*x+225*x^2+400*x^3+225*x^4+36*x^5+x^6)/(1-x)^7. [Colin Barker, Mar 15 2012]

Prog

(Maxima) A008388[n]:=1+7*n*(n+1)*(n^2+n+3)*(11*n^2+11*n+14)/60$
makelist(A008388[n], n, 0, 30); /* Martin Ettl, Oct 26 2012 */

Crossrefs

Sequence in context: A184153 A184145 A238202 * A241939 A251896 A060888

Adjacent sequences: A008385 A008386 A008387 * A008389 A008390 A008391

Keyword

nonn,easy

Author

N. J. A. Sloane and J. H. Conway

Status

approved