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A379050 a(n) = b(b(n)), where b(k) = A121053(k).

%I A379050 #10 Dec 20 2024 11:08:05
%S A379050 1,3,5,7,2,11,13,19,23,17,37,41,29,53,67,31,73,89,43,103,107,47,127,
%T A379050 139,59,163,61,167,71,191,197,211,79,229,83,241,97,263,283,101,307,
%U A379050 313,109,331,347,113,353,401,131,419,137,439,149,443,479,151,487,157,509,541,173,563,577,179,601,181,607,643,193,647,199,661,673,727,223,761,227,787,233,797,821,239
%N A379050 a(n) = b(b(n)), where b(k) = A121053(k).
%C A379050 Suggested by the formula a(a(n)) = 2*n + 3 for the analogous sequence A079000.
%H A379050 Michael De Vlieger, <a href="/A379050/b379050.txt">Table of n, a(n) for n = 1..10000</a>
%t A379050 nn = 2^8; a[1] = 2; u = 4; v = {1}; w = {2}; p = 3;
%t A379050 Do[If[MemberQ[w, n], k = p;
%t A379050   w = Append[DeleteCases[w, n], p]; p = NextPrime[p],
%t A379050   If[Length[v] == 0,
%t A379050     k = u; AppendTo[w, u],
%t A379050     k = First[v]; v = Rest[v]]];
%t A379050   Set[{a[n]}, {k}];
%t A379050   If[n + 1 >= u, u++; While[PrimeQ[u], u++]], {n, 2, nn}];
%t A379050 {1}~Join~TakeWhile[Array[a[a[#]] &, nn], IntegerQ] (* _Michael De Vlieger_, Dec 17 2024 *)
%Y A379050 Cf. A079000, A121053.
%K A379050 nonn
%O A379050 1,2
%A A379050 _N. J. A. Sloane_, Dec 14 2024