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A364824 Index of prime(n) in A067836, or -1 if prime(n) does not occur in it.

%I A364824 #11 Oct 15 2023 11:59:17
%S A364824 1,2,3,4,6,5,7,8,9,12,13,10,19,14,20,16,26,42,18,25,11,15,17,43,118,
%T A364824 33,24,31,29,212,40,68,30,98,22,45,34,109,28,39,21,23,46,143,27,35,37,
%U A364824 55,47,123,58,90,132,32,139,91,41,44,38,52,36,77,54,48,53,83,51
%N A364824 Index of prime(n) in A067836, or -1 if prime(n) does not occur in it.
%C A364824 All terms in A067836 are distinct, making this sequence defined.
%C A364824 If the conjecture holds that A067836 contains only primes, then a(A062894(n)) = n.
%C A364824 If all primes eventually occur in A067836, then all terms in this sequence are positive and A062894(a(n)) = n.
%o A364824 (Python)
%o A364824 from itertools import count
%o A364824 from sympy import prime, nextprime
%o A364824 def A364824(n):
%o A364824     a, f, p = 2, 1, prime(n)
%o A364824     for i in count(1):
%o A364824         if a == p:
%o A364824             return i
%o A364824         a=nextprime((f:=f*a)+1)-f # _Chai Wah Wu_, Sep 09 2023
%Y A364824 Cf. A062894, A067836.
%K A364824 nonn
%O A364824 1,2
%A A364824 _Bert Dobbelaere_, Aug 09 2023