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A249689 Numbers n such that A084937(3n) > A084937(3n+1). 2
16, 65, 91, 1514, 1993, 1994, 2452, 2722, 3047, 3214, 3931, 3957, 4356, 4366, 5191, 5581, 5805, 5806, 7519, 8871, 9228, 9752, 10036, 10037, 10039, 10040, 10963, 10964, 11278, 11279, 12015, 12281, 12595, 12665, 13262, 13618, 13648, 15102, 15103, 18529, 18991 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..641 (Based on John P. Linderman's computation of a million terms of A084937)

PROG

(AWK, using a-file for A084937)

awk ' BEGIN {s = 0}

      NR%3 == 0 { s = $2 }

      NR%3 == 1 { t = $2

          if (s > t)

             print( (NR-1)/3 )

        } ' a084937.txt | awk '{ print NR, $1}' >b249689.txt

(Python)

from __future__ import division

from fractions import gcd

A249689_list, l1, l2, s, b = [], 2, 1, 3, set()

for n in range(3, 10**4):

....i = s

....while True:

........if not i in b and gcd(i, l1) == 1 and gcd(i, l2) == 1:

............l2, l1 = l1, i

............b.add(i)

............if l2 > l1 and n % 3 == 1:

................A249689_list.append((n-1)//3)

............while s in b:

................b.remove(s)

................s += 1

............break

........i += 1 # Chai Wah Wu, Dec 12 2014

CROSSREFS

Cf. A084937

Sequence in context: A294584 A041492 A257107 * A043402 A044154 A044535

Adjacent sequences:  A249686 A249687 A249688 * A249690 A249691 A249692

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Nov 12 2014

STATUS

approved

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Last modified September 29 17:14 EDT 2020. Contains 337432 sequences. (Running on oeis4.)