cp's OEIS Frontend

A060266 Difference between 2n and the following prime.

%I A060266 #20 Nov 28 2023 14:26:48
%S A060266 1,1,1,3,1,1,3,1,1,3,1,5,3,1,1,5,3,1,3,1,1,3,1,5,3,1,5,3,1,1,5,3,1,3,
%T A060266 1,1,5,3,1,3,1,5,3,1,7,5,3,1,3,1,1,3,1,1,3,1,13,11,9,7,5,3,1,3,1,5,3,
%U A060266 1,1,9,7,5,3,1,1,5,3,1,5,3,1,3,1,5,3,1,5,3,1,1,9,7,5,3,1,1,3,1,1,11,9,7,5
%N A060266 Difference between 2n and the following prime.
%H A060266 Michael De Vlieger, <a href="/A060266/b060266.txt">Table of n, a(n) for n = 1..10000</a>
%F A060266 Conjecture: Limit_{n->oo} (Sum_{k=1..n} a(k)) / (Sum_{k=1..n} log(2*k)) = 1. - _Alain Rocchelli_, Oct 24 2023
%p A060266 with(numtheory): [seq(nextprime(2*i)-2*i,i=1..256)];
%t A060266 d2n[n_]:=Module[{c=2n},NextPrime[c]-c]; Array[d2n,120] (* _Harvey P. Dale_, May 14 2011 *)
%t A060266 Table[NextPrime@ # - # &[2 n], {n, 120}] (* _Michael De Vlieger_, Feb 18 2017 *)
%o A060266 (PARI) a(n) = nextprime(2*n+1) - 2*n; \\ _Michel Marcus_, Feb 19 2017
%Y A060266 Cf. A020482, A049653, A060267, A060268, A060264.
%K A060266 nonn
%O A060266 1,4
%A A060266 _Labos Elemer_, Mar 23 2001