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A141284 Nonprimes of the form ((p(max)-1)*..*p*(p(min)+2)), where (p(max))*..*p*(p(min) = k(n) =n-th composite. 3
4, 8, 8, 10, 16, 16, 24, 20, 16, 24, 32, 30, 40, 32, 28, 48, 30, 48, 48, 32, 50, 64, 42, 48, 72, 60, 64, 72, 80, 60, 88, 64, 54, 80, 80, 96, 72, 70, 96, 90, 112, 96, 120, 90, 64, 84, 120, 128, 110, 120, 96, 144, 100, 144, 90, 144, 128, 90, 160, 144, 112, 168, 140, 160 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Replace one instance of the largest prime factor A052369(n) in the n-th composite by A052369(n)-1,

one instance of the smallest prime factor A056608(n) in the n-th composite by A056608(n)+2,

and if the result is composite, add it to the sequence. In summary, the sequence

contains composites of the form A002808(n)*(A052369(n)-1)*(A056608(n)+2)/(A052369(n)*A056608(n)).

LINKS

Table of n, a(n) for n=1..64.

EXAMPLE

If k(1)=4=(p(max)=2)*(p(min)=2), then (2-1)*(2+2)=1*4=4 .

If k(2)=8=(p(max)=3)*(p(min)=2), then

(3-1)*(2+2)=2*4=8 .

If k(3)=8=(p(max)=2)*(p=2)*(p(min)=2), then

(2-1)*2*(2+2)=1*2*4=8, etc.

CROSSREFS

Sequence in context: A029679 A304651 A187768 * A272812 A273207 A145154

Adjacent sequences:  A141281 A141282 A141283 * A141285 A141286 A141287

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov Aug 08 2008

EXTENSIONS

Definition and examples corrected and entries checked by R. J. Mathar, Mar 29 2010

STATUS

approved

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Last modified October 23 08:57 EDT 2019. Contains 328345 sequences. (Running on oeis4.)