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 A178375 #11 Feb 21 2021 03:41:50 %S A178375 2,3,2,5,1,7,2,3,1,11,1,13,1,1,2,17,1,19,1,1,2,23,1,5,1,3,1,29,1,31,2, %T A178375 7,1,3,1,37,1,7,1,41,1,43,2,1,2,47,1,7,2,1,3,53,1,7,1,1,2,59,1,61,1,1, %U A178375 2,7,1,67,3,1,1,71,1,73,2,1,1,5,1,79,1,7,1,83,1,2,2,7,2,89,1 %N A178375 The greatest common prime divisor of A000032(n)-1 and A001608(n), or 1 if no such divisor exists. %C A178375 If n is prime, then n divides c(n). If n is composite and divides c(n) it is a pseudoprime to both the Lucas (Bruckman) and Perrin tests, which is the intersection of A005845 and A013998. %C A178375 Conjecture: Records of the sequence are consecutive primes. %Y A178375 Cf. A000032, A001608, A178380, A005845, A013998. %K A178375 nonn %O A178375 2,1 %A A178375 _Vladimir Shevelev_, May 26 2010 %E A178375 More terms from _R. J. Mathar_, Aug 08 2010