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A366473 a(1) = 1; thereafter a(n) = A337136(n) + A337136(n-1).

%I A366473 #12 Jun 21 2025 01:56:49
%S A366473 1,3,5,8,9,10,14,15,16,19,29,48,41,53,94,67,81,82,31,47,78,60,31,80,
%T A366473 82,42,43,64,67,158,160,51,42,44,38,39,58,62,66,67,234,237,75,74,72,
%U A366473 75,78,82,86,90,91,94,97,145,147,101,152,153,106,110,111,112,115,81,83,143,148,129,127,190,193,259,263,333,332,137,205,212,147,149,226,223,297
%N A366473 a(1) = 1; thereafter a(n) = A337136(n) + A337136(n-1).
%H A366473 Michael De Vlieger, <a href="/A366473/b366473.txt">Table of n, a(n) for n = 1..10000</a>
%H A366473 Michael De Vlieger, <a href="/A366473/a366473.png">Log log scatterplot of a(n)</a>, n = 1..2^14, accentuating prime powers in red.
%t A366473 nn = 120;
%t A366473   c[_] := False;
%t A366473   Array[Set[{a[#], c[#]}, {#, True}] &, 2]; Set[{i, j, u},
%t A366473    Range[3]]; s = i + j;
%t A366473   Do[k = u;
%t A366473     While[Or[c[k], CoprimeQ[s, k]], k++];
%t A366473     Set[{a[n], c[k], i, j, s}, {s, True, j, k, j + k}];
%t A366473     If[k == u, While[c[u], u++]], {n, 2, nn}];
%t A366473 Array[a, nn] (* _Michael De Vlieger_, Oct 26 2023 *)
%Y A366473 Cf. A337136.
%K A366473 nonn
%O A366473 1,2
%A A366473 _N. J. A. Sloane_, Oct 26 2023