|
%I #12 Mar 15 2023 12:22:06
%S 3,7,23,43,113,157,277,347,509,821,937,1361,1657,1811,2179,2767,3433,
%T 3671,4423,4973,5261,6163,6823,7841,9319,10103,10513,11351,11777,
%U 12659,16007,17033,18637,19183,22063,22651,24499,26407,27733,29759,31873,32587,36293
%N First prime after phi(prime(n)^2).
%C The sequence always increases.
%H G. C. Greubel, <a href="/A079477/b079477.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A151800(A036689(n)). - _Michel Marcus_, Mar 15 2023
%e p_3=5, phi(5^2)=phi(25)=20, therefore a(3)=23
%p a:= n-> nextprime(2*binomial(ithprime(n),2)):
%p seq(a(n), n=1..44); # _Alois P. Heinz_, Mar 15 2023
%t Prime[1+PrimePi[EulerPhi[Prime[Range[41]]^2]]] (* _T. D. Noe_, Nov 15 2006 *)
%o (PARI) forprime (p=2,200, print1(nextprime(eulerphi(p^2))","))
%Y Cf. A036689, A151800.
%K nonn
%O 1,1
%A _Jon Perry_, Jan 15 2003
%E Corrected by _T. D. Noe_, Nov 15 2006
|
