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 A255549 #10 Mar 15 2016 05:09:55
%S A255549 2,11,61,121,253,379,663,945,1377,1687,2143,2803,3543,4053,5485,6315,
%T A255549 7023,7987,8781,9871,11559,13105,14743,16485,18337,19959,23073,24511,
%U A255549 26371,27895,30355,33789,36925,39273,42177,44167,50455,53221,55447,58935,61921,65625,70065,73321,78031,81513,84361,87963,96937,100075
%N A255549 Main diagonal of Unlucky array: a(n) = A255543(n,n).
%C A255549 a(n) = the n-th number in the infinite subset of unlucky numbers removed at the stage n in the lucky number sieve.
%F A255549 a(n) = A255543(n,n).
%t A255549 rows = cols = 50; L = 2 Range[0, 10^5] + 1; A = Join[{2 Range[cols]}, Reap[For[n = 2, n <= rows, r = L[[n++]]; L0 = L; L = ReplacePart[L, Table[r i -> Nothing, {i, 1, Length[L]/r}]]; Sow[Complement[L0, L][[1 ;; cols]]]]][[2, 1]]]; Table[A[[n, n]], {n, 1, Min[rows, cols]}] (* _Jean-François Alcover_, Mar 15 2016 *)
%o A255549 (Scheme) (define (A255549 n) (A255543bi n n)) ;; Code for A255543bi given in A255543.
%Y A255549 Cf. A219178, A255543, A255550.
%K A255549 nonn
%O A255549 1,1
%A A255549 _Antti Karttunen_, Feb 26 2015