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A308289 Lexicographically earliest sequence of distinct nonprimes such that a(n) + a(n+1) is prime.

%I A308289 #22 Feb 28 2024 10:46:30
%S A308289 1,4,9,8,15,14,27,10,21,16,25,6,35,12,49,18,55,24,65,32,39,20,33,26,
%T A308289 45,22,51,28,69,34,63,38,75,52,57,40,87,44,93,46,81,50,77,30,119,48,
%U A308289 91,36,95,42,85,54,125,56,111,62,105,58,99,64,115,66,133,60,121,70,123,68,129,82,117,74,153,76,135,88,141,86,143,80,147,92
%N A308289 Lexicographically earliest sequence of distinct nonprimes such that a(n) + a(n+1) is prime.
%H A308289 Carole Dubois, <a href="/A308289/b308289.txt">Table of n, a(n) for n = 1..3654</a>
%e A308289 The sequence starts with 1, 4, 9, 8, 15, 14, 27, 10, 21, 16, 25, ... and we see that:
%e A308289 a(1) + a(2) = 1 + 4 = 5 (a prime);
%e A308289 a(2) + a(3) = 4 + 9 = 13 (a prime);
%e A308289 a(3) + a(4) = 9 + 8 = 17 (a prime);
%e A308289 a(4) + a(5) = 8 + 15 = 23 (a prime); etc.
%Y A308289 Essentially the same as A075570.
%K A308289 base,nonn
%O A308289 1,2
%A A308289 _Eric Angelini_ and _Carole Dubois_, May 18 2019