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 A026469 #12 Sep 01 2015 14:53:28 %S A026469 1,3,4,5,6,7,8,9,11,12,13,14,15,16,19,20,21,22,23,24,27,28,29,30,31, %T A026469 33,35,36,38,39,40,42,43,44,46,47,48,49,51,53,54,55,56,57,59,60,62,63, %U A026469 64,66,67,68,69,70,71,75,76,77,78,79 %N A026469 a(1) = 1; for n > 1, a(n) = least positive integer > a(n-1) and not equal to a(i)^2 + a(j)^2 for 1<=i<=j<=n-1. %p A026469 # return true if 'candid' is allowed (not a sum of squares) %p A026469 A026469aux := proc(a,candid) local i,j ; for j from 1 to nops(a) do for i from 1 to j do if (op(i,a))^2+(op(j,a))^2 = candid then RETURN(false) ; fi ; od ; od ; RETURN(true) ; end: %p A026469 A026469 := proc(nmax) local a,candidat ; a := [1] ; while nops(a) < nmax do candidat := op(nops(a),a)+1 ; while A026469aux(a,candidat) = false do candidat := candidat+1 ; od ; a := [op(a),candidat] ; od: RETURN(a) ; end: A026469(60) ; # _R. J. Mathar_, Nov 01 2006 %Y A026469 A022544 is a subsequence. %Y A026469 Cf. A026468. %K A026469 nonn %O A026469 1,2 %A A026469 _Clark Kimberling_ %E A026469 Corrected by _Franklin T. Adams-Watters_, Oct 25 2006 %E A026469 Definition corrected by _N. J. A. Sloane_, Nov 01 2006