A008386 Crystal ball sequence for A_5 lattice.

1, 31, 271, 1281, 4251, 11253, 25493, 51563, 95693, 166003, 272755, 428605, 648855, 951705, 1358505, 1894007, 2586617, 3468647, 4576567, 5951257, 7638259, 9688029, 12156189, 15103779, 18597509

Offset

0,2

Comments

Partial sums of A008385.

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 (6,-15,20,-15,6,-1).

Formula

a(n) = (2*n+1)*(63*n^4+126*n^3+217*n^2+154*n+60)/60. - T. D. Noe, Apr 29 2007

G.f.: (1+x)*(1+24*x+76*x^2+24*x^3+x^4)/(1-x)^6. - Colin Barker, Mar 16 2012

Mathematica

LinearRecurrence[{6, -15, 20, -15, 6, -1}, {1, 31, 271, 1281, 4251, 11253}, 30] (* Harvey P. Dale, Apr 08 2018 *)

Crossrefs

Sequence in context: A180471 A125368 A126526 * A161558 A336279 A156094

Adjacent sequences: A008383 A008384 A008385 * A008387 A008388 A008389

Keyword

nonn,easy

Author

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

Status

approved