S000480


Record minimum values in A092693 = sum of iterated phi(n).

0, 1, 3, 7, 9, 15, 19, 27, 31, 35, 39, 55, 71, 79, 111, 123, 143, 159, 183, 223, 287, 319, 363, 367, 447, 495, 639, 655, 735, 895, 991, 1039, 1159, 1279, 1311, 1455, 1471, 1631, 1775, 1791, 1951, 1983, 2079, 2319, 2623, 2911, 2943, 3055, 3263, 3343, 3551

1

S000480

This is the value found at x = A181660(n).

T. D. Noe, Plot of 300 terms

T. D. Noe, Table of 300 terms

(Mma) nMax = 200000; a = Table[0, {nMax}]; Do[e = EulerPhi[n]; a[[n]] = e + a[[e]], {n, 2, nMax}]; m1 = {}; mn = Infinity; Do[If[a[[n]] < mn, mn = a[[n]]; AppendTo[m1, {n, mn}]], {n, nMax/2, 1, -1}]; m1 = Reverse[m1]; m2 = {}; mn = Infinity; Do[If[a[[n]] < mn, mn = a[[n]]; AppendTo[m2, {n, mn}]], {n, nMax, 1, -1}]; m2 = Reverse[m2]; i = 1; While[m1[[i]] == m2[[i]], i++]; i = i - 1; Transpose[Take[m1, i]][[2]]

Cf. A092693,  A181660.

nonn

T. D. Noe, Feb 17 2015

© Tony D Noe 2014-2015