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 A154287 #3 Mar 30 2012 17:37:58
%S A154287 1,3,6,9,13,18,23,29,35,42,49,57,66,75,85,95,106,117,129,141,154,167,
%T A154287 181,195,210,225,241,258,275,293,311,330,349,369,389,410,431,453,475,
%U A154287 498,521,545,569
%N A154287 (L)-sieve transform of {1,4,9,16,...,n^2,...}=A000290.
%C A154287 See A152009 for the definition of the (L)-sieve transform.
%C A154287 It appears that the first difference of {a(n)} starts with 2, followed by two occurrences of each consecutive integer except for the powers of 2, which occur only once, i.e. (2,3,3,4,5,5,6,6,7,7,8,9,9,...}. This has been verified for several hundred terms.
%Y A154287 A000290, A152009
%K A154287 nonn
%O A154287 1,2
%A A154287 _John W. Layman_, Jan 06 2009