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a(n) = Sum_{j=1..n} phi(n)^j.
0

%I #7 May 25 2024 21:24:26

%S 1,2,14,30,1364,126,335922,87380,12093234,1398100,111111111110,

%T 22369620,116719860413532,94036996914,40210710958664,321685687669320,

%U 314824432191309680912,121871948002098,749896248023298716143374

%N a(n) = Sum_{j=1..n} phi(n)^j.

%e n = 5: phi(5) = 4, 4+16+64+256+1024 = 1364;

%e n = 22: phi(22) = 10, a(22) = 10+100+...+10^22 = 11111111111111111111110;

%e n = 101: phi(101) = 100, a(101) = 1010101.....010100, etc.

%t Table[Apply[Plus, Table[EulerPhi[w]^j, {j, 1, w}]], {w, 1, 25}]

%Y Cf. A000010 (phi).

%K easy,nonn

%O 1,2

%A _Labos Elemer_, Sep 26 2002