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 A174742 #23 Sep 08 2022 08:45:51 %S A174742 2,3,13,37,43,47,59,73,89,97,103,107,113,127,131,137,151,167,173,179, %T A174742 181,191,193,199,223,227,233,239,241,251,257,263,269,277,307,313,317, %U A174742 331,353,359,367,373,383,397,419,421,433,439,443,461,479,487,503,521,523,541,557,563,569,571,577,587,593,599,601,607,613 %N A174742 Smallest of three consecutive primes whose sum is not a prime. %F A174742 A000040 \ A073681. %t A174742 Prime[Select[Range[1000], ! PrimeQ[Prime[#] + Prime[# + 1] + Prime[# + 2]] &]] %t A174742 Transpose[Select[Partition[Prime[Range[200]],3,1],!PrimeQ[ Total[#]]&]] [[1]] (* _Harvey P. Dale_, Jun 04 2013 *) %o A174742 (Magma) [NthPrime(n): n in [1..150] | not IsPrime(NthPrime(n) + NthPrime(n+1) + NthPrime(n+2))]; // _Vincenzo Librandi_ Mar 16 2020 %Y A174742 Cf. A073681. %K A174742 nonn %O A174742 1,1 %A A174742 _Robert Wintner_, Nov 30 2010