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A008922 Crystal ball sequence for lattice {E_7}*. 1
1, 57, 995, 8683, 48429, 198677, 653791, 1825719, 4494329, 10016209, 20601723, 39670115, 72292453, 125732205, 210093239, 339085039, 530914929, 809317097, 1204728211, 1755619419, 2509994525, 3527064133 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

Index entries for crystal ball sequences

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 linear recurrences with constant coefficients, signature (8, -28, 56, -70, 56, -28, 8, -1).

FORMULA

G.f.: (1+x)*(x^6+624*x^5+1959*x^4+1744*x^3+519*x^2+48*x+1)/(1-x)^8.

PROG

(PARI) a(n)=([0, 1, 0, 0, 0, 0, 0, 0; 0, 0, 1, 0, 0, 0, 0, 0; 0, 0, 0, 1, 0, 0, 0, 0; 0, 0, 0, 0, 1, 0, 0, 0; 0, 0, 0, 0, 0, 1, 0, 0; 0, 0, 0, 0, 0, 0, 1, 0; 0, 0, 0, 0, 0, 0, 0, 1; -1, 8, -28, 56, -70, 56, -28, 8]^n*[1; 57; 995; 8683; 48429; 198677; 653791; 1825719])[1, 1] \\ Charles R Greathouse IV, Feb 10 2017

CROSSREFS

Sequence in context: A233370 A008390 A231311 * A116181 A208601 A000505

Adjacent sequences:  A008919 A008920 A008921 * A008923 A008924 A008925

KEYWORD

nonn,nice,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified January 18 23:05 EST 2019. Contains 319282 sequences. (Running on oeis4.)