The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A113569 Least number, k which is a multiple of a primorial, such that p-n*k, p-(n-1)k, p-(n-2)k, ... p-2k, p-k, p, p+k, p+2k, ... p+(n-2)k, p+(n-1)k and p+n*k are all prime with p being the k-th prime. 0
 2, 6, 720, 252420, 2053380 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE a(1)=2 which is a multiple of a primorial. a(2)=6 because p=13 and p-6=7 & p+6=19 all of which are prime and 6 is of the form 2*3*m, A002110. a(3)=720 because p=5443 and p-720=4723, p-2*720=4003, p+720=6163 & p+2*720=6883 all of which are prime and 720 is of the form 2*3*5*m. a(4)=252420 because p MATHEMATICA f[n_] := Block[{p = Fold[Times, 1, Prime[ Range[ n]]]}, CROSSREFS Cf. A064403, A112530. Sequence in context: A180492 A169661 A047690 * A252739 A178773 A046857 Adjacent sequences:  A113566 A113567 A113568 * A113570 A113571 A113572 KEYWORD hard,nonn AUTHOR Robert G. Wilson v, Sep 10 2005 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 17 09:03 EDT 2021. Contains 343969 sequences. (Running on oeis4.)