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A258934 Half the difference between the 2n-th prime and the n-th prime, starting from n=2.

%I A258934 #17 Sep 08 2022 08:46:13
%S A258934 2,4,6,9,12,13,17,19,21,24,26,30,32,33,39,40,45,48,51,54,57,58,67,66,
%T A258934 69,74,78,81,84,83,90,90,99,100,104,108,110,115,118,121,126,126,132,
%U A258934 133,140,140,140,147,156,162,165,168,171,172,175,175,185,185,189
%N A258934 Half the difference between the 2n-th prime and the n-th prime, starting from n=2.
%C A258934 The differences between odd prime numbers are always even, so a(n) is well defined for n>=2.
%H A258934 Seiichi Manyama, <a href="/A258934/b258934.txt">Table of n, a(n) for n = 2..10000</a>
%F A258934 a(n) = ( prime(2*n) - prime(n) ) / 2.
%F A258934 a(n) = A072473(n)/2.
%t A258934 Table[(Prime[2 k] - Prime[k])/2, {k, 2, 60}]
%o A258934 (Sage) [(nth_prime(2*n)-nth_prime(n))/2 for n in (2..60)] # _Bruno Berselli_, Jun 15 2015
%o A258934 (Magma) [(NthPrime(2*n)-NthPrime(n))/2: n in [2..60]]; // _Bruno Berselli_, Jun 15 2015
%Y A258934 Cf. A072473, A072715, A087461.
%K A258934 nonn,easy
%O A258934 2,1
%A A258934 _Federico Provvedi_, Jun 15 2015