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 A153347 #14 Sep 08 2022 08:45:39 %S A153347 2,4,6,7,8,10,12,13,14,16,17,18,19,20,21,22,24,25,26,27,28,30,31,32, %T A153347 34,36,37,38,40,42,43,44,46,47,48,49,50,52,54,55,56,57,58,60,61,62,63, %U A153347 64,65,66,67,68,70,71,72,73,74,76,77,78,79,80,82,84,85,86,87,88,90,91,92 %N A153347 Numbers n>0 such that 7*n-4 is not prime. %H A153347 Vincenzo Librandi, <a href="/A153347/b153347.txt">Table of n, a(n) for n = 1..1000</a> %e A153347 Distribution of the odd terms in the following triangular array: %e A153347 *; %e A153347 *,*; %e A153347 *,*,*; %e A153347 *,7,*,*; %e A153347 *,*,*,*,*; %e A153347 *,*,*,*,21,*; %e A153347 7,*,*,*,*,*,*; %e A153347 *,*,*,*,*,*,37,*; %e A153347 *,*,*,25,*,*,*,*,*; %e A153347 *,*,*,*,*,*,*,*,*,*; %e A153347 *,17,*,*,*,*,*,*,63,*,*; %e A153347 *,*,*,*,*,47,*,*,*,*,*,*; %e A153347 *,*,*,*,43,*,*,*,*,*,*,97,*; %e A153347 13,*,*,*,*,*,*,71,*,*,*,*,*,*; etc. %e A153347 where * marks the non-integer values of (4*h*k + 2*k + 2*h + 5)/7 with h >= k >= 1. - _Vincenzo Librandi_, Jan 17 2013 %t A153347 Select[Range[1, 200], !PrimeQ[7 # - 4]&] (* _Vincenzo Librandi_, Jan 13 2013 *) %o A153347 (Magma) [n: n in [1..150] | not IsPrime(7*n-4)]; // _Vincenzo Librandi_, Jan 13 2013 %Y A153347 Cf. A024903. %K A153347 nonn,easy %O A153347 1,1 %A A153347 _Vincenzo Librandi_, Dec 24 2008 %E A153347 Erroneous comment deleted by _N. J. A. Sloane_, Jun 23 2010