A049454 - OEIS

%I #18 Dec 01 2024 03:48:42

%S 1,2,3,7,11,27,31,67,83,119,135,235,251,395,431,495,559,815,851,1175,

%T 1239,1383,1483,1967,2031,2431,2575,2899,3043,3827,3891,4791,5047,

%U 5447,5703,6279,6423,7719,8043,8619,8875,10475,10619,12383

%N a(n) = 1 + Sum_{i=1..n} phi(i)^2.

%H Harvey P. Dale, <a href="/A049454/b049454.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = A057434(n) + 1 for n >= 1. - _Amiram Eldar_, Dec 01 2024

%t Table[1+Sum[EulerPhi[i]^2,{i,n}],{n,0,50}] (* _Harvey P. Dale_, Mar 21 2020 *)

%t Join[{1}, 1 + Accumulate[EulerPhi[Range[45]]^2]] (* _Amiram Eldar_, Dec 01 2024 *)

%o (PARI) a(n) = 1 + sum(i=1, n, eulerphi(i)^2); \\ _Michel Marcus_, Mar 07 2020

%Y Cf. A000010 (phi), A005728, A057434, A127473.

%K nonn

%O 0,2

%A _N. J. A. Sloane_