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 A253593 #23 Jan 15 2015 20:42:52
%S A253593 1,2,3,4,4,4,4,4,5,9,9,9,9,9,9,16,16,16,16,16,16,16,16,16,16,16,16,16,
%T A253593 16,17,22,22,28,28,28,28,28,28,36,36,39,39,39,39,39,39,39,45,45,45,45,
%U A253593 45,45,45,45,52,52,52,52,52,52,52,52,52,52,52,52
%N A253593 a(n) is the largest of the first n terms in A098550 for which the numbers 1 to a(n) are a subset, pretending all primes present.
%e A253593 a(9) = 5 because the first 9 terms in A098550 are {1, 2, 3, 4, 9, 8, 15, 14, 5}, and {1, 2, 3, 4, 5} is a subset.
%e A253593 a(10) = 9 because the first 10 terms in A098550 are {1, 2, 3, 4, 9, 8, 15, 14, 5, 6}; and pretending that prime 7 is present, {1, 2, 3, 4, 5, 6, 7, 8, 9} is a subset.
%Y A253593 Cf. A098550, A253591.
%K A253593 nonn,easy
%O A253593 1,2
%A A253593 _Bob Selcoe_, Jan 04 2015
%E A253593 Name improved and 2 terms corrected by _Hans Havermann_, Jan 06 2015