A217141 - OEIS

%I #8 Sep 27 2012 16:28:43

%S 143,157,203,247,273,1147,1209,1679,2147,2279,2375,2445,2705,2747,

%T 4331,4687,5049,6107,7367,7835,7869,7979,7991,9167,12127,17145,18501,

%U 18753,18981,19803,22987,26733,27359,29097,29987,32829,35485,35763,37653,37851,39907

%N Numbers n such that phi(n) = phi(n+12) and are not divisible by 2.

%H Donovan Johnson, <a href="/A217141/b217141.txt">Table of n, a(n) for n = 1..1000</a>

%o (PARI) {op=vector(N=12); Nd6=N/6;for( n=1, 1e4, if( op[n%N+1]+0==op[n%N+1]=eulerphi(n), if ((n-N) % Nd6 != 0, print1(n-N, ", "))))}

%Y Cf. A000010, A179188, A217139.

%K nonn

%O 1,1

%A _Michel Marcus_, Sep 27 2012