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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A090821 Numbers that are products of two consecutive nonprimes. 0
 4, 24, 48, 72, 90, 120, 168, 210, 240, 288, 360, 420, 462, 528, 600, 650, 702, 756, 840, 960, 1056, 1122, 1190, 1260, 1368, 1482, 1560, 1680, 1848, 1980, 2070, 2208, 2352, 2450, 2550, 2652, 2808, 2970, 3080, 3192, 3306, 3480, 3720, 3906, 4032, 4160, 4290 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..47. EXAMPLE The nonprimes: 1,4,6,8,9,10,12,14,15 ..., product of consecutive nonprimes: 4,24,48,72,90,... MATHEMATICA With[{nonps=Complement[Range[100], Prime[Range[PrimePi[100]]]]}, Times @@@ Partition[nonps, 2, 1]] (* Harvey P. Dale, Jan 16 2012 *) CROSSREFS Cf. A018252. Sequence in context: A080380 A364278 A039935 * A226575 A052645 A353250 Adjacent sequences: A090818 A090819 A090820 * A090822 A090823 A090824 KEYWORD easy,nonn AUTHOR Felix Tubiana, Feb 11 2004 EXTENSIONS Definition clarified by Harvey P. Dale, Jan 16 2012 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.

Last modified April 24 14:32 EDT 2024. Contains 371960 sequences. (Running on oeis4.)