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 A336370 #16 Jul 19 2023 15:16:45 %S A336370 2,3,5,7,11,17,19,23,25,29,31,33,35,37,41,43,47,49,53,55,59,61,67,71, %T A336370 73,75,77,79,83,85,87,89,91,97,101,103,107,109,111,113,119,125,127, %U A336370 131,133,137,139,143,145,149,151,155,157,161,163,165,167,169,171 %N A336370 Numbers k such that gcd(k, prime(k) + prime(k-1)) = 1. %e A336370 In the following table, p(k) = A000040(k) = prime(k). %e A336370 k p(k) p(k)+p(k-1) gcd %e A336370 2 3 5 1 %e A336370 3 5 8 1 %e A336370 4 7 12 4 %e A336370 5 11 18 1 %e A336370 6 13 24 6 %e A336370 2 and 3 are in this sequence; 4 and 6 are in A336371; 3 and 5 are in A336372; 7 and 13 are in A336373. %t A336370 p[n_] := Prime[n]; %t A336370 u = Select[Range[2, 200], GCD[#, p[#] + p[# - 1]] == 1 &] (* this sequence *) %t A336370 v = Select[Range[2, 200], GCD[#, p[#] + p[# - 1]] > 1 &] (* A336371 *) %t A336370 Prime[u] (* A336372 *) %t A336370 Prime[v] (* A336373 *) %Y A336370 Cf. A000040, A001043, A336366, A336371, A336372, A336373. %K A336370 nonn %O A336370 1,1 %A A336370 _Clark Kimberling_, Oct 04 2020 %E A336370 Offset corrected by _Mohammed Yaseen_, Jun 02 2023