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 A270191 #9 Mar 20 2016 12:55:51 %S A270191 1,4,6,8,12,14,19,22,25,27,29,31,34,38,42,44,48,50,53,59,61,63,65,68, %T A270191 70,75,78,80,82,85,88,90,93,95,101,106,112,115,117,122,125,127,131, %U A270191 134,136,138,141,143,145,147,149,151,153,155,157,159,163,169,172,175,177,181,183,189,191,193,198,204,207,211,213,217,222 %N A270191 Numbers n for which (prime(n+1)-prime(n)) mod 3 = 1. %H A270191 Antti Karttunen, <a href="/A270191/b270191.txt">Table of n, a(n) for n = 1..10000</a> %e A270191 1 is present as prime(2)-prime(1) = 3-2 = 1 = 1 mod 3. %e A270191 4 is present as prime(5)-prime(4) = 11-7 = 4 = 1 mod 3. %t A270191 Select[Range@ 222, Mod[Prime[# + 1] - Prime@ #, 3] == 1 &] (* _Michael De Vlieger_, Mar 17 2016 *) %o A270191 (Scheme, with _Antti Karttunen_'s IntSeq-library) %o A270191 (define A270191 (MATCHING-POS 1 1 (lambda (n) (= 1 (A137264 n))))) %o A270191 (PARI) isok(n) = ((prime(n+1) - prime(n)) % 3) == 1; \\ _Michel Marcus_, Mar 17 2016 %Y A270191 Subsequence of A270189. %Y A270191 Positions of ones in A137264. %Y A270191 Cf. A000040, A001223, A270190, A270192. %K A270191 nonn %O A270191 1,2 %A A270191 _Antti Karttunen_, Mar 16 2016