A289818 Primes of the form k!3-27, where k!3 is the triple factorial number (A007661).
53, 853, 3613, 24344293, 72642169573, 2576442067869429759973, 38900816605808456499199973, 26070192823309041523916799973, 17978533302590087193373917833428087202627190783999999973
Offset: 1
Keywords
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..21
- Henri & Renaud Lifchitz, PRP Records.Search for n!3-27.
- Joe McLean, Interesting Sources of Probable Primes
- OpenPFGW Project, Primality Tester
Crossrefs
Cf. A247463.
Programs
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Mathematica
MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]]; Select[Table[MultiFactorial[i, 3] - 27, {i, 7, 100}], PrimeQ[#]&] Select[Table[Times@@Range[n,1,-3]-27,{n,7,150}],PrimeQ] (* Harvey P. Dale, Mar 08 2020 *)