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 A065131 #18 Jan 08 2025 17:02:23
%S A065131 2,8,18,26,27,53,344,539,1221,6869,7271,10753,17742,33289,59688,
%T A065131 156649,949350,2291181,3115026,3283468,4148225,4493333,18012397,
%U A065131 80433020,218082214,268274214,639257836,4081484513,9373412685,28315174578,43438521639,208170358834
%N A065131 Arithmetic mean of first n terms of A001414 is an integer.
%F A065131 A025281(n)/n is an integer, where A025281(n+1)=A025281(n)+A001414(n) and A001414 is sum of primes dividing n (with repetition).
%e A065131 Sum of first 18 terms of A001414 gives A025281(18)=126 which is divisible by n=18, so 18 is a term: 0+2+3+4+5+5+7+6+6+7+11+7+13+9+8+8+17+8=126=7*18,
%t A065131 s=0; Do[s=s+lg[n]; If[IntegerQ[n/25000], Print[n]]; If[IntegerQ[s/n], Print[{n, s, s/n}]], {n, 2, 2000000}] where lg[n]=A001414(n).
%Y A065131 Cf. A025281, A001414.
%K A065131 nonn
%O A065131 1,1
%A A065131 _Labos Elemer_, Oct 15 2001
%E A065131 a(21)-a(29) from _Donovan Johnson_, Apr 25 2010
%E A065131 a(30)-a(31) from _Donovan Johnson_, Jun 11 2011
%E A065131 a(32) from _Donovan Johnson_, Feb 26 2014