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!)
A057017 Product of first n composite numbers minus 1 is a prime. 1
1, 2, 3, 9, 12, 22, 26, 30, 34, 51, 54, 100, 125, 155, 168, 173, 220, 401, 494 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
EXAMPLE
a(3) = 3 because 4*6*8-1 = 191 which is prime.
MATHEMATICA
Composite[ n_Integer ] := (k = n + PrimePi[ n ] + 1; While[ k - PrimePi[ k ] - 1 != n, k++ ]; k); Do[ m = n; If[ PrimeQ[ Product[ Composite[ k ], {k, 1, n} ] - 1 ], Print[ n ] ], {n, 1, 1980} ]
CROSSREFS
Cf. A053982.
Sequence in context: A048084 A350439 A067719 * A330298 A330242 A239859
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Apr 21 2001
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 29 09:14 EDT 2024. Contains 371268 sequences. (Running on oeis4.)