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A249689 Numbers k such that A084937(3k) > A084937(3k+1).

%I A249689 #25 Jun 23 2025 17:26:08
%S A249689 16,65,91,1514,1993,1994,2452,2722,3047,3214,3931,3957,4356,4366,5191,
%T A249689 5581,5805,5806,7519,8871,9228,9752,10036,10037,10039,10040,10963,
%U A249689 10964,11278,11279,12015,12281,12595,12665,13262,13618,13648,15102,15103,18529,18991
%N A249689 Numbers k such that A084937(3k) > A084937(3k+1).
%H A249689 N. J. A. Sloane, <a href="/A249689/b249689.txt">Table of n, a(n) for n = 1..641</a> (Based on _John P. Linderman_'s computation of a million terms of A084937)
%o A249689 (AWK)
%o A249689 # Using a-file for A084937.
%o A249689 awk ' BEGIN {s = 0}
%o A249689       NR%3 == 0 { s = $2 }
%o A249689       NR%3 == 1 { t = $2
%o A249689           if (s > t)
%o A249689              print( (NR-1)/3 )
%o A249689         } ' a084937.txt | awk '{ print NR, $1}' >b249689.txt
%o A249689 (Python)
%o A249689 from math import gcd
%o A249689 A249689_list, l1, l2, s, b = [], 2, 1, 3, set()
%o A249689 for n in range(3,10**4):
%o A249689     i = s
%o A249689     while True:
%o A249689         if not i in b and gcd(i,l1) == 1 and gcd(i,l2) == 1:
%o A249689             l2, l1 = l1, i
%o A249689             b.add(i)
%o A249689             if l2 > l1 and n % 3 == 1:
%o A249689                 A249689_list.append((n-1)//3)
%o A249689             while s in b:
%o A249689                 b.remove(s)
%o A249689                 s += 1
%o A249689             break
%o A249689         i += 1 # _Chai Wah Wu_, Dec 12 2014
%Y A249689 Cf. A084937
%K A249689 nonn
%O A249689 1,1
%A A249689 _N. J. A. Sloane_, Nov 12 2014