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a(n) is the smallest k such that A360097(k) = n.
0

%I #33 Feb 17 2023 20:30:31

%S 13,14,20,7,5,10,4,9,63,6,42,1590,1,2,5172911835,974749335,21,26135070

%N a(n) is the smallest k such that A360097(k) = n.

%o (PARI)

%o a360097(n)=my(k=1);while(isprime(2*n*k-1)||isprime(2*n*k+1),k++);k

%o a(n)=for(i=1,+oo,my(k=a360097(i));if(k==n,return(i)))

%Y Cf. A018252, A124522, A360097.

%K nonn,more

%O 1,1

%A _Jean-Marc Rebert_, Feb 01 2023