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Search: id:A051925
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A051925 n(2n+5)(n-1)/6. +0
5
0, 0, 3, 11, 26, 50, 85, 133, 196, 276, 375, 495, 638, 806, 1001, 1225, 1480, 1768, 2091, 2451, 2850, 3290, 3773, 4301, 4876, 5500, 6175, 6903, 7686, 8526, 9425, 10385, 11408, 12496, 13651, 14875, 16170, 17538, 18981, 20501, 22100, 23780 (list; graph; listen)
OFFSET

0,3

COMMENT

Related to variance of number of inversions of a random permutation of n letters.

REFERENCES

V. N. Sachkov, Probablistic Methods in Combinatorial Analysis, Cambridge, 1997.

J. Wang and H. Li, The upper bound of essential chromatic numbers of hypergraphs, Discr. Math. 254 (2002), 555-564.

MAPLE

a:=n->sum((n+j^2), j=0..n): seq(a(n), n=-1..40); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 27 2006

seq(sum(k^2-1 , k=1..n), n=0..41); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 28 2008

CROSSREFS

Adjacent sequences: A051922 A051923 A051924 this_sequence A051926 A051927 A051928

Sequence in context: A025529 A124078 A096795 this_sequence A011942 A101612 A123928

KEYWORD

nonn

AUTHOR

njas, Dec 19 1999

page 1

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Last modified May 16 01:24 EDT 2008. Contains 139630 sequences.


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