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%I #13 May 07 2022 09:26:48
%S 3,6,11,13,16,19,22,24,28,33,37,41,43,48,50,55,62,64,67,70,73,75,81,
%T 84,86,93,95,98,106,109,111,115,120,124,127,129,138,142,145,147,150,
%U 158,162,164,168,170,173,182,186,189,191,196,198,203,211,215,218,220,223
%N Numbers k such that A002977(k) - A002977(k-1) = 1.
%H Amiram Eldar, <a href="/A073942/b073942.txt">Table of n, a(n) for n = 1..10000</a>
%H Amiram Eldar, <a href="/A073942/a073942.jpg">Plot of a(n)/n for n = 20000..650000</a>
%F Conjecture : a(n) is asymptotic to c*n where c is around 3.8...
%t max = 1500; s = Union @ Flatten[NestWhileList[Flatten[{2*# + 1, 3*# + 1}] &, 1, Min[#1] < max &]]; 1 + Position[Differences[Select[s, # <= max &]], 1] // Flatten (* _Amiram Eldar_, May 07 2022 *)
%Y Cf. A002977.
%K nonn
%O 1,1
%A _Benoit Cloitre_, Nov 20 2002