Search: a252371 -id:a252371
|
|
A251727
|
|
Numbers n > 1 for which gpf(n) > spf(n)^2, where spf and gpf (smallest and greatest prime factor of n) are given by A020639(n) and A006530(n).
|
|
+10
13
|
|
|
10, 14, 20, 22, 26, 28, 30, 33, 34, 38, 39, 40, 42, 44, 46, 50, 51, 52, 56, 57, 58, 60, 62, 66, 68, 69, 70, 74, 76, 78, 80, 82, 84, 86, 87, 88, 90, 92, 93, 94, 98, 99, 100, 102, 104, 106, 110, 111, 112, 114, 116, 117, 118, 120, 122, 123, 124, 126, 129, 130, 132, 134, 136, 138, 140, 141, 142, 145, 146, 148, 150, 152
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Numbers n > 1 for which the smallest r such that r^k <= spf(n) and gpf(n) < r^(k+1) [for some k >= 0] is gpf(n)+1. Here spf and gpf (smallest and greatest prime factor of n) are given by A020639(n) and A006530(n). (The original, equivalent definition of the sequence).
Numbers n > 1 for which there doesn't exist any r <= gpf(n) such that r^k <= spf(n) and gpf(n) < r^(k+1), for some k >= 0, where spf and gpf (smallest and greatest prime factor of n) are given by A020639(n) and A006530(n).
|
|
LINKS
|
|
|
PROG
|
|
|
CROSSREFS
|
Gives the positions of zeros in A252374 following its initial term.
Cf. A252371 (difference between the prime indices of gpf and spf of each a(n)).
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Antti Karttunen, Dec 17 2014. A new simpler definition found Jan 01 2015 and the original definition moved to the Comments section
|
|
STATUS
|
approved
|
|
|
|
|
|
|
0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 2, 0, 0, 2, 0, 3, 0, 0, 1, 0, 1, 1, 0, 0, 0, 4, 0, 2, 5, 1, 0, 0, 0, 2, 0, 1, 0, 0, 6, 3, 0, 0, 0, 0, 0, 4, 1, 0, 0, 1, 1, 2, 0, 0, 0, 5, 1, 0, 0, 0, 0, 1, 0, 0, 2, 2, 0, 1, 0, 0, 0, 6, 3, 0, 1, 7, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 2, 0, 4, 0, 0, 8, 0, 0, 0
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,17
|
|
LINKS
|
|
|
FORMULA
|
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
Search completed in 0.007 seconds
|