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 A100426 #3 Mar 30 2012 17:22:34 %S A100426 2,4,6,10,8,18,24,40,80,84,144,176,224,384,360,464,480,544,704,864, %T A100426 840,864,1012,1184,1280,1344,1320,1640,1904,2016,2384,2496,2864,2600, %U A100426 2976,3104,3240,3824,3560,4544,4784,4704,5184,5264,5376,5664,5600,6080,5640 %N A100426 A sieve transform applied to Euler's phi function A000010 starting at 4. %t A100426 (* see A100424 for the definition of SieveTransform *) SieveTransform[EulerPhi[Range[4, 20000]]] %Y A100426 Cf. A099361, A100424, A100425. %K A100426 nonn %O A100426 1,1 %A A100426 _T. D. Noe_, Nov 19 2004