A016924 - OEIS

%I #18 Mar 28 2022 07:41:05

%S 1,2401,28561,130321,390625,923521,1874161,3418801,5764801,9150625,

%T 13845841,20151121,28398241,38950081,52200625,68574961,88529281,

%U 112550881,141158161,174900625,214358881,260144641,312900721,373301041,442050625,519885601,607573201,705911761

%N a(n) = (6*n + 1)^4.

%H Vincenzo Librandi, <a href="/A016924/b016924.txt">Table of n, a(n) for n = 0..2000</a>

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).

%F From _Amiram Eldar_, Mar 28 2022: (Start)

%F a(n) = A016921(n)^4 = A016922(n)^2.

%F Sum_{n>=0} 1/a(n) = PolyGamma(3, 1/6)/7776. (End)

%t (6Range[0,30]+1)^4 (* _Harvey P. Dale_, May 18 2011 *)

%o (Magma) [(6*n+1)^4: n in [0..50]]; // _Vincenzo Librandi_, May 04 2011

%Y Cf. A016921, A016922, A016923, A016925, A016926.

%K nonn,easy

%O 0,2

%A _N. J. A. Sloane_