OFFSET
0,2
REFERENCES
S. R. Finch, Mathematical Constants, Cambridge, 2003, Section 1.6.3.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..2000
Index entries for linear recurrences with constant coefficients, signature (4, -6, 4, -1).
FORMULA
Sum_{n>=0} 1/a(n) = Pi^3/(36*sqrt(3)) + 91*zeta(3)/216.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - Wesley Ivan Hurt, Dec 28 2023
MATHEMATICA
a[n_]:=(6*n + 1)^3; Array[a, 60, 0] (* or *)
LinearRecurrence[{4, -6, 4, -1}, {1, 343, 2197, 6859}, 60] (* or *)
CoefficientList[Series[(1 + 339 x + 831 x^2 + 125 x^3)/(-1 + x)^4, {x, 0, 60}], x] (* Stefano Spezia, Sep 03 2018 *)
PROG
(Magma) [(6*n+1)^3: n in [0..60]]; // Vincenzo Librandi, May 04 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved