A163443 Primes p such that floor(p^3/27) is prime.
17, 31, 103, 157, 179, 193, 233, 733, 827, 1097, 1129, 1327, 1543, 1597, 1723, 1831, 1889, 1907, 2069, 2137, 2393, 2677, 2803, 3163, 3257, 3433, 3617, 3797, 4261, 4999, 5233, 5237, 5309, 5449, 5701, 5939, 6079, 6173, 6637, 6781, 6961, 7069, 7321, 7879
Offset: 1
Keywords
Examples
p=17 is in the sequence because [(17/3)^3] = [181.963] = 181 is prime. p=31 is in the sequence because [(31/3)^3] = [1103.37] = 1103 is prime.
Links
- G. C. Greubel, Table of n, a(n) for n = 1..1000
Crossrefs
Programs
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Mathematica
f[n_]:=IntegerPart[(p/3)^3]; lst={};Do[p=Prime[n];If[PrimeQ[f[p]],AppendTo[lst, p]],{n,7!}];lst
Extensions
Introduced standard terminology in the definition - R. J. Mathar, Aug 02 2009