A027866 - OEIS

%I #29 Oct 12 2022 16:16:28

%S 2,3,4,9,12,13,18,19,21,23,24,32,34,38,48,51,52,56,62,63,81,82,87,96,

%T 97,102,104,109,119,128,142,146,152,158,159,164,166,167,199,212,214,

%U 217,219,221,223,224,229,233,236,238,249,251,258,269,273,277,284,291,296

%N Numbers k such that k^2 + (k+1)^2 + (k+2)^2 + (k+3)^2 + (k+4)^2 + (k+5)^2 is prime.

%C Numbers k such that 55 + 30*k + 6*k^2 is prime. - _Zak Seidov_, May 20 2014

%H Zak Seidov, <a href="/A027866/b027866.txt">Table of n, a(n) for n = 1..10000</a>

%H Patrick De Geest, <a href="http://www.worldofnumbers.com/index.html">World!Of Numbers</a>

%t Select[Range[6!], PrimeQ[#^2 + (# + 1)^2 + (# + 2)^2 + (# + 3)^2 + (# + 4)^2 + (# + 5)^2] &] (* _Vladimir Joseph Stephan Orlovsky_, Dec 20 2009 *)

%t Select[Range[300],PrimeQ[6#^2+30#+55]&] (* _Harvey P. Dale_, Oct 12 2022 *)

%o (Magma) [n: n in [0..400] | IsPrime(55+30*n+6*n^2)]; // _Vincenzo Librandi_, Nov 18 2010

%o (PARI) is(n)=isprime(n^2+(n+1)^2+(n+2)^2+(n+3)^2+(n+4)^2+(n+5)^2) \\ _Charles R Greathouse IV_, Feb 17 2017

%K nonn

%O 1,1

%A _Patrick De Geest_