login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A251415 Values of A098550 where A098550(n)/n reaches a new high-water mark. 3
1, 9, 15, 25, 35, 329, 581, 679, 3443, 5753, 6941, 9229, 10417, 11561, 14963, 30043, 45071, 120107, 135187, 150137, 255221, 1786819, 2552567, 2807737, 3063077, 4849921, 14549573, 33948953, 38798741, 43648643, 63048061, 72747599, 82447327, 87297191 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The prime factorizations of these numbers are 1, 3^2, 3*5, 5^2, 5*7, 7*47, 7*83, 7*97, 11*313, 11*523, 11*631, 11*839, 11*947, 11*1051, 13*1151, 13*2311, 13*3467, 13*9239, 13*10399, 13*11549, 17*15013, 17*105107, ... It would be nice to know what this is trying to tell us!
LINKS
PROG
(Python)
from fractions import gcd
A251415_list, l1, l2, s, u, l, b = [1], 3, 2, 4, 1, 1, {}
for n in range(4, 10**4):
....i = s
....while True:
........if not i in b and gcd(i, l1) == 1 and gcd(i, l2) > 1:
............l2, l1, b[i] = l1, i, 1
............while s in b:
................b.pop(s)
................s += 1
............if u*n < i*l:
................A251415_list.append(i)
................u, l = i, n
............break
........i += 1 # Chai Wah Wu, Dec 06 2014
CROSSREFS
Sequence in context: A319529 A249730 A342418 * A109888 A193227 A014003
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Dec 02 2014
EXTENSIONS
a(23)-a(26) added and typo in definition corrected by Chai Wah Wu, Dec 06 2014
a(27)-a(34) from David Applegate, Dec 18 2014
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)