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!)
A252478 Products of a semiprime times a larger prime. 2
20, 28, 42, 44, 52, 66, 68, 76, 78, 92, 99, 102, 110, 114, 116, 117, 124, 130, 138, 148, 153, 164, 170, 171, 172, 174, 186, 188, 190, 207, 212, 222, 230, 236, 238, 244, 246, 255, 258, 261, 266, 268, 279, 282, 284, 285, 290, 292, 310, 316, 318, 322, 332, 333, 345, 354, 356, 366, 369, 370 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Primitive elements of the sequence A137428 of numbers which have a composite divisor smaller than their largest prime factor: That sequence consists of all multiples of the terms of this sequence.
LINKS
FORMULA
A252478 = { s*p ; s in A001358, p in A000040 and p > s }.
PROG
(PARI) is(n)={bittest(12, #f=factor(n)~) && f[1, #f]^2>n && setsearch([[2, 1], [1, 1, 1]], f[2, ])}
CROSSREFS
Sequence in context: A350841 A361867 A309769 * A124318 A309780 A139703
KEYWORD
nonn
AUTHOR
M. F. Hasler, Jan 02 2015
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 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)