A069073 a(n) = n*(4n^2 - 1)^2.

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

Table of n, a(n) for n=0..29.

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

Cf. A006752, A069075.

Sequence in context: A239479 A229625 A196965 * A156086 A160478 A020263

Adjacent sequences: A069070 A069071 A069072 * A069074 A069075 A069076

Keyword

easy,nonn

Author

Benoit Cloitre, Apr 05 2002

Status

approved