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A008382 Floor(n/5)*floor((n+1)/5)*floor((n+2)/5)*floor((n+3)/5)*floor((n+4)/5). 3
0, 0, 0, 0, 0, 1, 2, 4, 8, 16, 32, 48, 72, 108, 162, 243, 324, 432, 576, 768, 1024, 1280, 1600, 2000, 2500, 3125, 3750, 4500, 5400, 6480, 7776, 9072, 10584, 12348, 14406, 16807, 19208, 21952, 25088, 28672 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,7

LINKS

Table of n, a(n) for n=0..39.

Index entries for linear recurrences with constant coefficients, signature (2, -1, 0, 0, 4, -8, 4, 0, 0, -6, 12, -6, 0, 0, 4, -8, 4, 0, 0, -1, 2, -1).

FORMULA

a(n)= +2*a(n-1) -a(n-2) +4*a(n-5) -8*a(n-6) +4*a(n-7) -6*a(n-10) +12*a(n-11) -6*a(n-12) +4*a(n-15) -8*a(n-16) +4*a(n-17) -a(n-20) +2*a(n-21) -a(n-22). - R. J. Mathar, May 08 2013

G.f. x^5 *(x^10 -2*x^9 +4*x^8 -4*x^7 +8*x^6 -8*x^5 +8*x^4 -4*x^3 +4*x^2 -2*x+1) *(1+x)^2  / ( (x^4+x^3+x^2+x+1)^4 *(x-1)^6 ). - R. J. Mathar, May 08 2013

PROG

(Maxima) A008382(n):=floor(n/5)*floor((n+1)/5)*floor((n+2)/5)*floor((n+3)/5)*floor((n+4)/5)$

makelist(A008382(n), n, 0, 30); /* Martin Ettl, Oct 26 2012 */

CROSSREFS

Sequence in context: A051505 A133408 A289275 * A208742 A222193 A217833

Adjacent sequences:  A008379 A008380 A008381 * A008383 A008384 A008385

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified September 24 18:54 EDT 2017. Contains 292433 sequences.