A289851 Primes of the form k!2 - 8, where k!2 is the double factorial number (A006882).
7, 97, 937, 654729067, 13113070457687988603440617, 563862029680583509947946867, 536347102817482913555411512425352545980058003572241486357421867, 352999527454840466971061863960307904899505075341088595453568994140617
Offset: 1
Keywords
Links
- Robert Price, Table of n, a(n) for n = 1..10
- Henri and Renaud Lifchitz, PRP Records.Search for n!2-8.
- Joe McLean, Interesting Sources of Probable Primes.
- OpenPFGW Project, Primality Tester.
Programs
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Mathematica
MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]]; Select[Table[MultiFactorial[i, 2] - 8, {i, 5, 100}], PrimeQ[#]&] Select[Range[5,100]!!-8,PrimeQ] (* Harvey P. Dale, Feb 06 2024 *)
Formula
Extensions
Definition corrected by Harvey P. Dale, Feb 06 2024