cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A111215 Numbers k such that 4k + 5 is prime.

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%I A111215 #35 Oct 28 2024 18:54:44
%S A111215 0,2,3,6,8,9,12,14,17,21,23,24,26,27,33,36,38,42,44,47,48,56,57,59,63,
%T A111215 66,68,69,72,77,78,83,86,87,92,96,98,99,101,104,107,111,113,114,126,
%U A111215 129,134,138,141,143,147,149,152,153,159,162,164,167,168,174,176,182,188
%N A111215 Numbers k such that 4k + 5 is prime.
%H A111215 Daniel Starodubtsev, <a href="/A111215/b111215.txt">Table of n, a(n) for n = 1..10000</a>
%F A111215 a(n) = A005098(n) - 1. - _Daniel Starodubtsev_, Feb 10 2020
%e A111215 If k=99 then 4k + 5 = 401 (prime).
%t A111215 Select[Range[0,200],PrimeQ[4#+5]&] (* _Harvey P. Dale_, Dec 07 2013 *)
%o A111215 (Magma) [n: n in [0..200] | IsPrime(4*n+5)]; // _Vincenzo Librandi_, Nov 13 2010
%o A111215 (PARI) is(n)=isprime(4*n+5) \\ _Charles R Greathouse IV_, Aug 31 2015
%Y A111215 Cf. A005098, A095278.
%K A111215 nonn,easy
%O A111215 1,2
%A A111215 _Parthasarathy Nambi_, Oct 24 2005