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 A143676 #6 Apr 02 2015 10:34:47
%S A143676 3,1,0,2,1,8,14,8,1,12,19,6,6,18,4,14,1,24,33,6,8,4,3,16,12,43,8,39,6,
%T A143676 20,41,6,5,16,64,4,8,7,12,55,63,32,7,12,12,63,9,10,66,72,38,1,24,6,68,
%U A143676 4,39,79,9,28,28,97,3,15,23,30,23,6,88,3,7,98,18,98,5,48,103,109,14,36,116,20
%N A143676 (0, 1, 2, 3, 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 2^2*3, 13,..) becomes (abs (0-1-2, 3-2-2, 5-2-3, 7-2-3, 3-2-2, 5-11-2, 2-3-13,..)).
%e A143676 Abs(0-1-2)=abs(-3)=3=a(1).
%e A143676 Abs(3-2-2)=abs(-1)=1=a(2).
%e A143676 Abs(5-2-3)=abs(0)=0=a(3).
%e A143676 Abs(7-2-3)=abs(2)=2=a(4).
%e A143676 Abs(3-2-2)=abs(-1)=1=a(5).
%e A143676 Abs(5-11-2)=abs(-8)=8 =a(6).
%e A143676 Abs(2-3-13)=abs(-14)=14=a(7), etc.
%p A143676 pflat2 := proc(nmax) local a, ifs, n, p, c ; a := [0,1] ; for n from 2 to nmax do ifs := ifactors(n)[2] ; for p in ifs do a := [op(a),op(1,p)] ; if op(2,p) > 1 then a := [op(a),op(2,p)] ; fi; od: od: a ; end: pL := pflat2(300) : for n from 1 to nops(pL)-4 by 3 do printf("%d,", abs(op(n, pL)-op(n+1, pL)-op(n+2,pL)) ) ; od: # _R. J. Mathar_, Nov 06 2008
%t A143676 Abs[#[[1]]-#[[2]]-#[[3]]]&/@Partition[Join[{0,1},Flatten[Table[ DeleteCases[ Flatten[FactorInteger[n]],1],{n,2,120}]]],3] (* _Harvey P. Dale_, Apr 02 2015 *)
%Y A143676 Cf. A141269, A141270.
%K A143676 nonn
%O A143676 1,1
%A A143676 _Juri-Stepan Gerasimov_, Nov 01 2008
%E A143676 Removed incompatibilities with internal OEIS format, extended, _R. J. Mathar_, Nov 06 2008