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A027864 Primes of the form k^2 + (k+1)^2 + (k+2)^2 = 3*(k+1)^2+2. 11

%I #41 Jul 18 2023 09:25:28

%S 5,29,149,509,677,1877,3677,8429,9749,11909,13469,17789,22709,27077,

%T 28229,45389,46877,53069,70229,72077,81677,100469,102677,114077,

%U 128549,141269,154589,180077,192029,195077,207509,223589,230189,261077,312989,340709

%N Primes of the form k^2 + (k+1)^2 + (k+2)^2 = 3*(k+1)^2+2.

%C Same as A257163 without its first term. - _Jonathan Sondow_, Oct 24 2015

%C The domain of k is not explicit. If the domain is all integers then the sequence A257163 is produced. In this sequence domain is all nonnegative integers. - _Michael Somos_, Oct 24 2015

%H Harvey P. Dale, <a href="/A027864/b027864.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Table[3n^2+6n+5,{n,0,400}],PrimeQ] (* _Harvey P. Dale_, Oct 22 2016 *)

%t Select[Table[Total[Range[n,n+2]^2],{n,0,500}],PrimeQ] (* _Harvey P. Dale_, May 23 2021 *)

%o (PARI) select(isprime, vector(100,n,3*n^2+2)) \\ _Charles R Greathouse IV_, Apr 17 2015

%o (Python)

%o from sympy import isprime

%o print(list(filter(isprime, (3*k**2+6*k+5 for k in range(350))))) # _Michael S. Branicky_, May 29 2021

%Y Cf. A027574, A257163.

%K nonn,easy

%O 1,1

%A _Patrick De Geest_

%E More terms from _Claudio Meller_, Jun 25 2009

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Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)