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 A222463 #21 Oct 09 2023 02:21:39
%S A222463 5,30,35,40,45,10,55,60,65,70,15,80,85,90,95,4,105,110,115,120,25,130,
%T A222463 135,140,145,30,155,160,165,170,35,180,185,190,195,40,205,210,215,220,
%U A222463 9,230,235,240,245,50,255,260,265,270,55,280,285,290,295,60
%N A222463 a(n) = n*5/gcd(n*5,n+5), n >= 5.
%C A222463 This is the fifth column (m=5) of the triangle A221918.
%H A222463 <a href="/index/Rec#order_50">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1).
%F A222463 a(n) = A221918(n,5) = numerator(n*5/(n+5)) = n*5/gcd(n*5,n+5) = n*5/gcd(25,n+5), n >= 5.
%F A222463 a(n) = 2*a(n-25)-a(n-50). - _Colin Barker_, Feb 25 2013
%F A222463 Sum_{k=5..n} a(k) ~ (521/250) * n^2. - _Amiram Eldar_, Oct 09 2023
%e A222463 a(10) = numerator(50/15) = numerator(10/3) = 10 = 50/gcd(50,15)= 50/5 = 50/gcd(25,15).
%t A222463 Table[(5n)/GCD[5n,n +5],{n,5,60}] (* _Harvey P. Dale_, Nov 06 2020 *)
%Y A222463 Cf. A221918, A000027 (m=1), A145979(m=2), A221920 (m=3), A221921 (m=4).
%K A222463 nonn,easy
%O A222463 5,1
%A A222463 _Wolfdieter Lang_, Feb 21 2013