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 A238098 #20 Sep 28 2023 12:34:17
%S A238098 0,0,1,1,2,3,4,5,7,8,10,12,13,15,19,21,23,25,27,30,34,36,39,44,46,49,
%T A238098 54,57,60,64,67,72,76,79,85,91,92,95,100,106,109,115,117,122,129,132,
%U A238098 136,147,150,154,159,163,166,174,180,187,191,194,199,210,211,216
%N A238098 Number of cubic polynomials with coefficients from {1..n} for which all three roots are integers.
%C A238098 A generalization of A006218 and A238096.
%H A238098 Dorin Andrica and Eugen J. Ionascu, <a href="http://www.emis.de/journals/ASUO/mathematics_/vol22-1/Andrica_D__Ionascu_E.J._nou-1__final_.pdf">On the number of polynomials with coefficients in [n]</a>, An. St. Univ. Ovidius Constanta, Vol. 22(1),2014, 13-23.
%F A238098 a(n) = Sum_{k=1..n} floor(n/k)*A238097(k).
%o A238098 (PARI) f(n) = if( n<1, 0, sum(a1=1, n, sum(a2=1, n, sum(a3=1, n, vecmax([a1, a2, a3]) == n && vecsum( factor( Pol([1, a1, a2, a3]))[, 2]) == 3)))); \\ A238097
%o A238098 a(n) = sum(k=1, n, (n\k)*f(k));
%o A238098 lista(nn) = my(v = vector(nn, k, f(k))); vector(nn, i, sum(k=1, i, (i\k)*v[k])); \\ _Michel Marcus_, Sep 28 2023
%Y A238098 Cf. A006218, A238096, A238097.
%K A238098 nonn
%O A238098 1,5
%A A238098 _N. J. A. Sloane_, Feb 22 2014