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!)
A090090 a(n) = prime(n)*prime(n+3). 7

%I #25 Sep 08 2022 08:45:12

%S 14,33,65,119,209,299,493,589,851,1189,1333,1739,2173,2537,2867,3551,

%T 4189,4453,5293,5893,6497,7663,8383,9167,10379,11009,11639,13589,

%U 14279,15481,17653,19519,20687,21823,24287,25217,27161,29177,30227,33043

%N a(n) = prime(n)*prime(n+3).

%e a(5) = prime(5)*prime(8) = 11*19 = 209.

%t Table[ Prime[n] Prime[n + 3], {n, 1, 40}] (* _Robert G. Wilson v_, Jan 22 2004 *)

%t First[#]*Last[#]&/@Partition[Prime[Range[200]],4,1] (* _Harvey P. Dale_, Dec 18 2011 *)

%o (Magma) [NthPrime(n)*NthPrime(n+3): n in [1..40]]; // _Vincenzo Librandi_, Feb 03 2020

%Y Subset of the squarefree semiprimes, A006881.

%Y Cf. A006094, A090076.

%K easy,nonn

%O 1,1

%A _Felix Tubiana_, Jan 21 2004

%E Extended by _Robert G. Wilson v_, Jan 22 2004

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 July 24 03:05 EDT 2024. Contains 374575 sequences. (Running on oeis4.)