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A069073
a(n) = n*(4n^2 - 1)^2.
0
0, 9, 450, 3675, 15876, 49005, 122694, 266175, 520200, 938961, 1592010, 2566179, 3967500, 5923125, 8583246, 12123015, 16744464, 22678425, 30186450, 39562731, 51136020, 65271549, 82372950, 102884175, 127291416, 156125025, 189961434, 229425075, 275190300, 327983301
OFFSET
0,2
REFERENCES
L. B. W. Jolley, Summation of Series, Dover, 1961, eq. (104) on page 20.
Konrad Knopp, Theory and application of infinite series, Dover, p. 269.
LINKS
Konrad Knopp, Theorie und Anwendung der unendlichen Reihen, Berlin, J. Springer, 1922. (Original German edition of "Theory and Application of Infinite Series")
FORMULA
Sum_{n>=1} 1/a(n) = 3/2 -2*log(2) = 0.113705638880109...
Sum_{n>=1} (-1)^(n+1)/a(n) = G + log(2) - 3/2, where G is Catalan's constant (A006752). - Amiram Eldar, Mar 08 2022
MATHEMATICA
a[n_] := n*(4*n^2 - 1)^2; Array[a, 40, 0] (* Amiram Eldar, Mar 08 2022 *)
CROSSREFS
Sequence in context: A239479 A229625 A196965 * A156086 A160478 A020263
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Apr 05 2002
STATUS
approved