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A272329 Indices of records in A272328. 0

%I #11 Mar 14 2020 16:48:56

%S 1,3,16,15,35,39,45,91,111,117,135,364,287,296,292,273,369,385,429,

%T 482,465,866,819,861,915,964,1154,1209,1281,1558,1448,1395,1845,1928,

%U 2432,2336,2308,2306,2275,2379,3472,3416,3285,3344,2583,3224,2715,2775,2896,3003

%N Indices of records in A272328.

%t 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 *)

%o (Sage) L=[sum([1 for k in [1..n] if euler_phi(n)==euler_phi(n+k)]) for n in [1..4000]]

%o print([L.index(i)+1 for i in [1..50]])

%Y Cf. A272328, A081375.

%K nonn

%O 1,2

%A _Tom Edgar_, Apr 25 2016

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Last modified April 19 16:52 EDT 2024. Contains 371794 sequences. (Running on oeis4.)