A229060 - OEIS

%I #9 Sep 08 2022 08:46:05

%S 2,3,5,7,11,13,17,19,23,31,37,43,53,59,67,73,79,83,101,109,113,127,

%T 137,151,157,163,167,173,179,181,191,197,199,223,227,229,233,239,251,

%U 257,269,271,281,283,307,317,331,337,347,359,367,373,389,409,421,431,433

%N Smallest of 13 consecutive primes whose sum is not a prime.

%H Vincenzo Librandi, <a href="/A229060/b229060.txt">Table of n, a(n) for n = 1..1000</a>

%e 31 is in the sequence because 31+37+41+43+47+53+59+61+67+71+73+79+83 = 745 and 745 = 5*149.

%t Transpose[Select[Partition[Prime[Range[200]], 13, 1], !PrimeQ[Total[#]]&]][[1]]

%o (Magma) [NthPrime(n): n in [1..120] | not IsPrime(&+[NthPrime(n+s): s in [0..12]])];

%Y Cf. A228201.

%K nonn

%O 1,1

%A _Vincenzo Librandi_, Sep 13 2013