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A292114 List of numbers n such that A039655(n) reaches a new record high. 4
2, 4, 9, 121, 301, 441, 468, 3171, 8373, 13440, 16641, 16804, 83161, 100652, 133200, 367428, 395640, 459680, 701823, 3739690, 4238314, 6698616, 9014248, 12301860, 16956850, 22230514, 54889200, 60676144, 84983056, 116648892, 128942664 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Naively, one might have expected these numbers to have some other distinguishing property (primorials, perhaps), but that seems not to be the case.
Increasingly many of the values are of the form m*p with a (large) prime p and a smooth m, often m = 2^k (for a(n), n = 12, 14, 21, 23, 26, 28, 29, ...) or m = 2^k*3^k' (n = 7, 9, 19, 22, 30, ...) or m = 2^k*5^k' (n = 20, 25, ...). I conjecture that almost all terms are even. Also, for most terms (n = 1, 2, 3, 4, 5, 7, 10, 12, 14, 15, 16, 17, 19, 20, 21, 23, 24, 25, 26, 29, 30, 31, ...), either a(n)-1 or a(n)+1 has at most 2 prime divisors. - M. F. Hasler, Sep 25 2017
LINKS
N. J. A. Sloane, Three (No, 8) Lovely Problems from the OEIS, Experimental Mathematics Seminar, Rutgers University, Oct 05 2017, Part I, Part 2, Slides. (Mentions this sequence)
PROG
(PARI) m=-n=1; until(print1(n", "), until(A039655(n++)>m, ); m=A039655(n)) \\ M. F. Hasler, Sep 25 2017
CROSSREFS
Sequence in context: A067603 A269739 A065299 * A128942 A364637 A328837
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 22 2017
EXTENSIONS
More terms from Hugo Pfoertner, Sep 22 2017
STATUS
approved

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Last modified March 19 03:33 EDT 2024. Contains 370952 sequences. (Running on oeis4.)