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%I A224531 #7 Oct 01 2015 11:52:50
%S A224531 0,1,2,3,4,6,5,8,10,12,15,16,20,24,30,13,21,26,28,36,42,51,64,68,80,
%T A224531 96,102,120,37,57,63,74,76,108,114,126,41,55,75,82,88,100,110,132,150,
%U A224531 35,39,45,52,56,70,72,78,84,90,65,104,105,112,130,140,144,156,168,180,210
%N A224531 Triangle in which row n > 1 has the n values x such that phi(x) = A007374(n), We define the first row to be 0.
%H A224531 T. D. Noe, <a href="/A224531/b224531.txt">Rows n = 1..100 of triangle, flattened</a>
%H A224531 D. Bressoud, <a href="http://www.macalester.edu/~bressoud/books/CNT.m">CNT.m</a> Computational Number Theory Mathematica package.
%e A224531 Triangle:
%e A224531 0,
%e A224531 1, 2,
%e A224531 3, 4, 6,
%e A224531 5, 8, 10, 12,
%e A224531 15, 16, 20, 24, 30,
%e A224531 13, 21, 26, 28, 36, 42,
%e A224531 51, 64, 68, 80, 96, 102, 120,
%e A224531 37, 57, 63, 74, 76, 108, 114, 126,
%e A224531 41, 55, 75, 82, 88, 100, 110, 132, 150
%t A224531 Needs["CNT`"]; nn = 10; t = Table[{}, {nn}]; n = 0; t[[1]] = {0}; left = nn - 1; While[left > 0, n++; p = PhiInverse[n]; cnt = Length[p]; If[cnt <= nn && t[[cnt]] == {}, t[[cnt]] = p; left--]]; t
%Y A224531 Cf. A066420, A224532 (numbers in the first column and diagonal).
%K A224531 nonn,tabl
%O A224531 1,3
%A A224531 _T. D. Noe_, Apr 11 2013

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