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A011898 a(n) = floor(n*(n-1)*(n-2)/16). 1
0, 0, 0, 0, 1, 3, 7, 13, 21, 31, 45, 61, 82, 107, 136, 170, 210, 255, 306, 363, 427, 498, 577, 664, 759, 862, 975, 1096, 1228, 1370, 1522, 1685, 1860, 2046, 2244, 2454, 2677, 2913, 3163, 3427, 3705, 3997, 4305 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

FORMULA

From R. J. Mathar, Apr 15 2010: (Start)

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-16) - 3*a(n-17) + 3*a(n-18) - a(n-19).

G.f.: x^4*(1+x^2+2*x^6-2*x^7+3*x^8-x^9+x^11+x^12-x^13+x^14) / ( (-1+x)^4*(1+x)*(1+x^2)*(1+x^4)*(1+x^8) ). (End)

MATHEMATICA

Table[Floor[(n(n-1)(n-2))/16], {n, 0, 50}] (* Harvey P. Dale, May 16 2012 *)

PROG

(MAGMA) [Floor(n*(n-1)*(n-2)/16): n in [0..50]]; // Vincenzo Librandi, May 21 2012

(PARI) a(n) = n*(n-1)*(n-2)\16; \\ Michel Marcus, Jan 14 2018

CROSSREFS

Sequence in context: A063541 A206246 A171965 * A098577 A004136 A147409

Adjacent sequences:  A011895 A011896 A011897 * A011899 A011900 A011901

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified October 13 20:38 EDT 2019. Contains 327981 sequences. (Running on oeis4.)