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 A239674 #13 May 19 2024 02:15:48 %S A239674 1,2,19,498,2114,8351,8381,59704,233890,291963,1119181,1507131, %T A239674 1839746,9768399,40844982,94852115,138032741,443653568,453853664, %U A239674 2491818901 %N A239674 Where records occur in A239656 (the first differences of sphenic numbers). %F A239674 A239656(a(n)) = A239673(n). %o A239674 (Haskell) %o A239674 a239674 n = a239674_list !! (n-1) %o A239674 -- See A239673 for definition of A239674_list. %o A239674 (PARI) list(lim)=my(v=List(), t); forprime(p=2, (lim)^(1/3), forprime(q=p+1, sqrt(lim\p), t=p*q; forprime(r=q+1, lim\t, listput(v, t*r)))); vecsort(Vec(v)) ; \\ A007304 %o A239674 chk(lim) = my(v=list(lim), dv = vector(#v-1, k, v[k+1] - v[k]), r=0); for (i=1, #dv, if (dv[i] > r, r=dv[i]; print1(i, ", "));); \\ _Michel Marcus_, Sep 20 2023 %Y A239674 Cf. A007304, A085809, A239656, A239673. %K A239674 nonn,more %O A239674 1,2 %A A239674 _Reinhard Zumkeller_, Mar 23 2014 %E A239674 a(12)-a(14) from _Michel Marcus_, Sep 20 2023 %E A239674 a(15)-a(20) from _Amiram Eldar_, May 19 2024