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A163431 Primes p such that floor(p^3/8) are also prime numbers. 4


%S 3,19,83,179,191,239,373,431,643,719,739,883,1123,1151,1171,1237,1283,

%T 1429,1459,1669,1811,2053,2083,2293,2351,2437,2579,2677,2687,2819,

%U 2851,2879,3167,3253,3491,3539,3877,4051,4099,4483,4549,4643,4799,5087,5171

%N Primes p such that floor(p^3/8) are also prime numbers.

%H Vincenzo Librandi, <a href="/A163431/b163431.txt">Table of n, a(n) for n = 1..1000</a>

%F A163430(n) = floor( a(n)^3/8 ).

%e a(1)=p=3 generates (3^3/8=3.375 where 3 isprime. a(2)=19 generates (19^3/8=857.275 where 857 is prime.

%t f[n_]:=IntegerPart[(p/2)^3]; lst={};Do[p=Prime[n];If[PrimeQ[f[p]],AppendTo[lst, p]],{n,7!}];lst

%K nonn,easy

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Jul 27 2009

%E Mathematica specific notation removed, comments moved to examples - _R. J. Mathar_, Sep 17 2009

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Last modified December 4 17:50 EST 2021. Contains 349526 sequences. (Running on oeis4.)