cp's OEIS Frontend

A340673 If n is of the form s^(2^e), where s is a squarefree number, and e >= 0, then a(n) is the (1+e)-th prime, otherwise a(n) = 1.

%I A340673 #21 Feb 07 2021 21:13:47
%S A340673 1,2,2,3,2,2,2,1,3,2,2,1,2,2,2,5,2,1,2,1,2,2,2,1,3,2,1,1,2,2,2,1,2,2,
%T A340673 2,3,2,2,2,1,2,2,2,1,1,2,2,1,3,1,2,1,2,1,2,1,2,2,2,1,2,2,1,1,2,2,2,1,
%U A340673 2,2,2,1,2,2,1,1,2,2,2,1,5,2,2,1,2,2,2,1,2,1,2,1,2,2,2,1,2,1,1,3,2,2,2,1,2
%N A340673 If n is of the form s^(2^e), where s is a squarefree number, and e >= 0, then a(n) is the (1+e)-th prime, otherwise a(n) = 1.
%H A340673 Antti Karttunen, <a href="/A340673/b340673.txt">Table of n, a(n) for n = 1..65537</a>
%H A340673 <a href="/index/Eu#epf">Index entries for sequences computed from exponents in factorization of n</a>
%F A340673 a(n) = A014963(A225546(n)).
%F A340673 a(n) = A225546(A340675(n)).
%F A340673 a(n) = A008578(1+A340676(n)).
%F A340673 If n is of the form s^(2^e), where s is a squarefree number, and e >= 0, then a(n) = A000040(1+e), otherwise a(n) = 1.
%o A340673 (PARI)
%o A340673 A008578(n) = if(1==n,n,prime(n-1));
%o A340673 A340673(n) = A008578(1+A340676(n)); \\ Uses also code from A340676.
%Y A340673 Cf. A000040, A008578, A014963, A225546, A340675, A340676.
%Y A340673 Positions of 1's: {1} U A340681, of 2's: A005117 \ {1}, of 3's: A062503 \ {1}, of 5's: A113849.
%Y A340673 Positions of terms > 1: A340682, of terms > 2: A340674.
%K A340673 nonn
%O A340673 1,2
%A A340673 _Antti Karttunen_, Jan 31 2021