This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A016815 #19 Nov 01 2024 21:09:51
%S A016815 1,125,729,2197,4913,9261,15625,24389,35937,50653,68921,91125,117649,
%T A016815 148877,185193,226981,274625,328509,389017,456533,531441,614125,
%U A016815 704969,804357,912673,1030301,1157625,1295029,1442897,1601613,1771561,1953125,2146689,2352637,2571353
%N A016815 a(n) = (4*n + 1)^3.
%D A016815 S. R. Finch, Mathematical Constants, Cambridge, 2003, Section 1.6.3.
%H A016815 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A016815 Sum_{n>=0} 1/a(n) = Pi^3/64 + 7 zeta(3)/16.
%F A016815 a(0)=1, a(1)=125, a(2)=729, a(3)=2197, a(n)=4*a(n-1)-6*a(n-2)+ 4*a(n-3)- a(n-4). - _Harvey P. Dale_, Sep 01 2013
%F A016815 G.f.: ( 1+121*x+235*x^2+27*x^3 ) / (x-1)^4 . - _R. J. Mathar_, Dec 03 2015
%F A016815 From _Stefano Spezia_, Nov 01 2024: (Start)
%F A016815 a(n) = A000578(A016813(n)).
%F A016815 E.g.f.: exp(x)*(1 + 124*x + 240*x^2 + 64*x^3). (End)
%t A016815 (4*Range[0,30]+1)^3 (* or *) LinearRecurrence[{4,-6,4,-1},{1,125,729,2197},30] (* _Harvey P. Dale_, Sep 01 2013 *)
%Y A016815 Cf. A000578, A016813.
%K A016815 nonn,easy
%O A016815 0,2
%A A016815 _N. J. A. Sloane_