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A294030 Values of bphi(n) = bphi(n+1), where bphi is the bi-unitary analog of Euler's totient function (A116550). 0

%I

%S 1,9,14,42,161,161,798,1400,86156,123656,419430

%N Values of bphi(n) = bphi(n+1), where bphi is the bi-unitary analog of Euler's totient function (A116550).

%C The bi-unitary totient function of numbers n such that n and n+1 have the same function value (A293184).

%C The bi-unitary version of A003275.

%F a(n) = A116550(A293184(n)).

%e 9 is in the sequence since 9 = bphi(14) = bphi(15).

%t bphi[1] = 1; bphi[n_] := With[{pp = Power @@@ FactorInteger[n]}, Count[Range[n], m_ /; Intersection[pp, Power @@@ FactorInteger[m]] == {}]]; a={}; b1=0; Do[b2 = bphi[k]; If[b1 == b2, a = AppendTo[a, b1]]; b1 = b2, {k, 1, 10^2}]; a (* after _Jean-Fran├žois Alcover_ at A116550 *)

%Y Cf. A116550, A293184.

%K nonn,more

%O 1,2

%A _Amiram Eldar_, Oct 22 2017

%E a(10)-a(11) from _Michel Marcus_, Nov 14 2017

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Last modified August 12 10:28 EDT 2020. Contains 336438 sequences. (Running on oeis4.)