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A016935
a(n) = (6*n + 2)^3.
14
8, 512, 2744, 8000, 17576, 32768, 54872, 85184, 125000, 175616, 238328, 314432, 405224, 512000, 636056, 778688, 941192, 1124864, 1331000, 1560896, 1815848, 2097152, 2406104, 2744000, 3112136
OFFSET
0,1
COMMENTS
The generating function is 8 times the g.f. of A016779. - R. J. Mathar, May 07 2008
FORMULA
a(n) = 8*A016779(n). - R. J. Mathar, May 07 2008
Sum_{n>=0} 1/a(n) = Pi^3 / (324*sqrt(3)) + 13*zeta(3)/216. - Amiram Eldar, Oct 02 2020
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - Wesley Ivan Hurt, Oct 02 2020
G.f.: 8*(1+60*x+93*x^2+8*x^3)/(-1+x)^4. - Wesley Ivan Hurt, Oct 02 2020
EXAMPLE
a(1) = (6*1 + 2)^3 = 8^3 = 512.
MATHEMATICA
(6*Range[0, 30]+2)^3 (* or *) LinearRecurrence[{4, -6, 4, -1}, {8, 512, 2744, 8000}, 30] (* Harvey P. Dale, Aug 23 2019 *)
PROG
(Magma) [(6*n+2)^3: n in [0..50]]; // Vincenzo Librandi, May 04 2011
KEYWORD
nonn,easy
STATUS
approved