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 A074501 #29 Apr 22 2025 02:48:40
%S A074501 3,8,30,134,642,3158,15690,78254,390882,1953638,9766650,48830174,
%T A074501 244144722,1220711318,6103532010,30517610894,152587956162,
%U A074501 762939584198,3814697527770,19073486852414,95367432689202,476837160300278
%N A074501 a(n) = 1^n + 2^n + 5^n.
%H A074501 Jason Bard, <a href="/A074501/b074501.txt">Table of n, a(n) for n = 0..1000</a>
%H A074501 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (8,-17,10).
%F A074501 From _Mohammad K. Azarian_, Dec 26 2008: (Start)
%F A074501 G.f.: 1/(1-x) + 1/(1-2*x) + 1/(1-5*x).
%F A074501 E.g.f.: e^x + e^(2*x) + e^(5*x). (End)
%F A074501 a(n) = 7*a(n-1) - 10*a(n-2) + 4 with a(0)=3, a(1)=8. - _Vincenzo Librandi_, Jul 21 2010
%t A074501 Table[1^n + 2^n + 5^n, {n, 0, 24}]
%o A074501 (PARI) a(n)=1+2^n+5^n \\ _Charles R Greathouse IV_, Jun 10 2011
%Y A074501 Equals A074600(n) + 1.
%Y A074501 Cf. A001550, A001576, A034513, A001579, A074502..A074580.
%K A074501 easy,nonn
%O A074501 0,1
%A A074501 _Robert G. Wilson v_, Aug 23 2002