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 A336371 #13 Jul 15 2023 17:49:12 %S A336371 4,6,8,9,10,12,13,14,15,16,18,20,21,22,24,26,27,28,30,32,34,36,38,39, %T A336371 40,42,44,45,46,48,50,51,52,54,56,57,58,60,62,63,64,65,66,68,69,70,72, %U A336371 74,76,78,80,81,82,84,86,88,90,92,93,94,95,96,98,99,100 %N A336371 Numbers k such that gcd(k, prime(k) + prime(k-1)) > 1. %F A336371 In the following table, p(k) = A000040(k) = prime(k). %F A336371 k p(k) p(k)+p(k-1) gcd %F A336371 2 3 5 1 %F A336371 3 5 8 1 %F A336371 4 7 12 4 %F A336371 5 11 18 1 %F A336371 6 13 24 6 %F A336371 2 and 3 are in A336370; 4 and 6 are in this sequence; 3 and 5 are in A336372; 7 and 13 are in A336373. %t A336371 p[n_] := Prime[n]; %t A336371 u = Select[Range[2, 200], GCD[#, p[#] + p[# - 1]] == 1 &] (* A336370 *) %t A336371 v = Select[Range[2, 200], GCD[#, p[#] + p[# - 1]] > 1 &] (* A336371 *) %t A336371 Prime[u] (* A336372 *) %t A336371 Prime[v] (* A336373 *) %Y A336371 Cf. A000040, A001043, A336366, A336370, A336372, A336373. %K A336371 nonn %O A336371 1,1 %A A336371 _Clark Kimberling_, Oct 04 2020 %E A336371 Offset corrected by _Mohammed Yaseen_, Jun 02 2023