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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A289686 Numbers k such that k!6 - 8 is prime, where k!6 is the sextuple factorial number (A085158). 1
 9, 11, 13, 15, 19, 27, 35, 39, 45, 51, 83, 99, 105, 111, 121, 123, 127, 133, 175, 177, 213, 263, 277, 285, 339, 347, 543, 681, 743, 1069, 1965, 2379, 2613, 2629, 2911, 3767, 3879, 4789, 5493, 5819, 11559, 14555, 17831, 19705, 24867, 37535, 85089 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Corresponding primes are: 19, 47, 83, 397, 1721, 229627, 21827567, ... a(48) > 10^5. Terms > 99 correspond to probable primes. LINKS Henri & Renaud Lifchitz, PRP Records. Search for n!6-8. Joe McLean, Interesting Sources of Probable Primes OpenPFGW Project, Primality Tester EXAMPLE 19!6 - 8 = 19*13*7 - 8 = 1721 is prime, so 19 is in the sequence. MATHEMATICA MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]]; Select[Range[8, 50000], PrimeQ[MultiFactorial[#, 6] - 8] &] CROSSREFS Cf. A007661, A037082, A084438, A123910, A242994. Sequence in context: A008558 A335912 A123760 * A251394 A155877 A214865 Adjacent sequences:  A289683 A289684 A289685 * A289687 A289688 A289689 KEYWORD nonn AUTHOR Robert Price, Jul 09 2017 EXTENSIONS a(47) from Robert Price, Aug 03 2018 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 May 20 21:39 EDT 2022. Contains 353876 sequences. (Running on oeis4.)