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 A130670 #10 Nov 08 2012 18:15:42 %S A130670 1,2,4,8,16,32,24,80,48,160,72,216,96,792,360,144,192,1056,1512,1080, %T A130670 240,288,432,1248,3200,1200,768,3120,480,576,2496,720,1536,864,6000, %U A130670 3600,2016,3072,960,3168,3744,1152,11664,2688,2400,2160,9792,1728,6240,9072 %N A130670 Smallest k such that phi(x) = k has exactly n even solutions. %H A130670 Vladeta Jovovic and Donovan Johnson, <a href="/A130670/b130670.txt">Table of n, a(n) for n = 1..1000</a> (first 100 terms from Vladeta Jovovic) %e A130670 a(3) = 4 because there are 3 even solutions (8, 10, 12) of phi(x) = 4 and for all k < 4 the number of even solutions of phi(x) = k is unequal to 3. %Y A130670 Cf. A007374, A130669. %K A130670 nonn %O A130670 1,2 %A A130670 _Franz Vrabec_, Jun 27 2007