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A011901 [ n(n-1)(n-2)/19 ]. 0
0, 0, 0, 0, 1, 3, 6, 11, 17, 26, 37, 52, 69, 90, 114, 143, 176, 214, 257, 306, 360, 420, 486, 559, 639, 726, 821, 923, 1034, 1153, 1282, 1419, 1566, 1722, 1889, 2066, 2254, 2453, 2664, 2886, 3120, 3366, 3625 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

LINKS

Table of n, a(n) for n=0..42.

FORMULA

a(n) = +3*a(n-1) -3*a(n-2) +a(n-3) +a(n-19) -3*a(n-20) +3*a(n-21) -a(n-22). [From R. J. Mathar, Apr 15 2010]

G.f.: (x^4 (1+x^4) (1+x^3 (1-x+x^3+x^6) (1+(-1+x) x (1+x^2))))/(1+x (-3+x (3+x (-1+(-1+x)^3 x^16)))). - Peter J. C. Moses, Jun 02 2014

CROSSREFS

Sequence in context: A107957 A000603 A003453 * A169739 A109471 A279032

Adjacent sequences:  A011898 A011899 A011900 * A011902 A011903 A011904

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified October 15 17:24 EDT 2019. Contains 328037 sequences. (Running on oeis4.)