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.
%I A215808 #48 Feb 25 2017 14:06:31 %S A215808 3,3,17,41,47,67,151,167,199,227,251,257,347,367,557,587,601,607,641, %T A215808 647,727,941,971,1051,1091,1097,1117,1181,1217,1277,1361,1427,1447, %U A215808 1447,1487,1487,1499,1607,1697,1741,1747,1741,1777,1877,1901,2087,2143,2281 %N A215808 Primes of the form 2*prime(k) - prime(k+1). %C A215808 Corresponding values of k: 3, 4, 9, 15, 16, 21, 37, 40, 47, 51, 55, 56, 71, 74, 103 (A216075). %H A215808 Zak Seidov, <a href="/A215808/b215808.txt">Table of n, a(n) for n = 1..1000</a> %e A215808 k=3: 2*5-7=3, k=4: 2*7-11=3, k=9: 2*23-29=17. %t A215808 pr=Prime[Range[1000]]; s=Select[2*Most[pr]-Rest[pr],PrimeQ] %t A215808 Select[2#[[1]]-#[[2]]&/@Partition[Prime[Range[500]],2,1],PrimeQ] (* _Harvey P. Dale_, Feb 25 2017 *) %Y A215808 Cf. A062234, A085704, A094104, A094105, A216075. %K A215808 nonn %O A215808 1,1 %A A215808 _Zak Seidov_, Sep 06 2012