A272329 Indices of records in A272328.
1, 3, 16, 15, 35, 39, 45, 91, 111, 117, 135, 364, 287, 296, 292, 273, 369, 385, 429, 482, 465, 866, 819, 861, 915, 964, 1154, 1209, 1281, 1558, 1448, 1395, 1845, 1928, 2432, 2336, 2308, 2306, 2275, 2379, 3472, 3416, 3285, 3344, 2583, 3224, 2715, 2775, 2896, 3003
Offset: 1
Keywords
Programs
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Mathematica
t = Table[Count[Range@ n, k_ /; EulerPhi@ n == EulerPhi[n + k]], {n, 3600}]; TakeWhile[Flatten[FirstPosition[t, #] & /@ Range@ Max@ t] /. n_ /; MissingQ@ n -> 0, # != 0 &] (* Michael De Vlieger, Apr 25 2016, Version 10.2 *) -
Sage
L=[sum([1 for k in [1..n] if euler_phi(n)==euler_phi(n+k)]) for n in [1..4000]] print([L.index(i)+1 for i in [1..50]])