A076246 - OEIS

A076246

Totients of those numbers at which values of A051547 increase: in these consecutive terms new prime powers arise, i.e., which did not occur in neither of preceding terms.

%I #13 Jul 30 2017 04:01:52

%S 2,4,6,10,8,16,18,22,28,46,32,52,58,54,82,64,100,102,106,148,162,166,

%T 172,178,190,196,226,250,128,256,262,268,282,292,310,316,346,358,366,

%U 382,388,466,478,486,502,508,556,562,568,586,606,618,642,652,676,708

%N Totients of those numbers at which values of A051547 increase: in these consecutive terms new prime powers arise, i.e., which did not occur in neither of preceding terms.

%e 8 = 2*2*2 immediately follows 10 = 2*5; 58 = 2*29 follows 52 = 2*2*13. In both cases, the latter term has a new prime factor (like 29) or an old one at a higher power (like 2*2*2).

%t s0=1; s1=1; Do[s0=s1; s1=LCM[s1, EulerPhi[n]]; If[ !Equal[s0, s1], Print[n]], {n, 1, 1000}]

%o (PARI) lista(nn) = {least = 1; for (n=2, nn, nleast = lcm(least, eulerphi(n)); if (nleast > least, print1(eulerphi(n), ", ")); least = nleast;);} \\ _Michel Marcus_, Jul 30 2017

%Y Cf. A003418, A051451, A051547, A076244, A076245.

%K nonn

%O 1,1

%A _Labos Elemer_, Oct 08 2002