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%I #17 Oct 05 2020 06:55:24
%S 1,216,1331,4096,9261,17576,29791,46656,68921,97336,132651,175616,
%T 226981,287496,357911,438976,531441,636056,753571,884736,1030301,
%U 1191016,1367631,1560896,1771561,2000376
%N a(n) = (5*n + 1)^3.
%H Amiram Eldar, <a href="/A016863/b016863.txt">Table of n, a(n) for n = 0..10000</a>
%H Eric Weisstein's MathWorld, <a href="http://mathworld.wolfram.com/PolygammaFunction.html">Polygamma Function</a>.
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Polygamma_function">Polygamma Function</a>.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F Sum_{n>=0} 1/a(n) = -polygamma(2, 1/5)/250. - _Amiram Eldar_, Oct 02 2020
%F a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - _Wesley Ivan Hurt_, Oct 02 2020
%F G.f.: (1+212*x+473*x^2+64*x^3)/(-1+x)^4. - _Wesley Ivan Hurt_, Oct 02 2020
%e a(0) = (5*0 + 1)^3 = 1.
%t Table[(5*n + 1)^3, {n, 0, 25}] (* _Amiram Eldar_, Oct 02 2020 *)
%Y Cf. A016861, A016862, A016864.
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_.
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