cp's OEIS Frontend

A167611 Nonprimes that are the sum of two consecutive nonprimes.

%I A167611 #38 Feb 06 2024 08:11:16
%S A167611 1,10,14,22,26,34,38,46,49,51,55,58,62,65,69,74,77,82,86,91,94,99,106,
%T A167611 111,115,118,122,125,129,134,142,146,153,155,158,161,166,169,171,175,
%U A167611 178,183,185,187,189,194,202,206,209,214,218,221,226,231,235,237,243
%N A167611 Nonprimes that are the sum of two consecutive nonprimes.
%C A167611 One and composite numbers that are the sum of two consecutive composite numbers.
%C A167611 Essentially the same as A151740 (except for initial term 1). - _Georg Fischer_, Oct 01 2018
%H A167611 Karl-Heinz Hofmann, <a href="/A167611/b167611.txt">Table of n, a(n) for n = 1..10000</a>
%e A167611 a(1) = 1st nonprime + 2nd nonprime = 0 + 1 =  1, which is nonprime;
%e A167611 a(2) = 3rd nonprime + 4th nonprime = 4 + 6 = 10, which is nonprime.
%o A167611 (Magma) m:=150; NonPrime:=[i: i in [0..m] | not IsPrime(i)]; [q: n in [1..#NonPrime-1] | not IsPrime(q) where q is NonPrime[n]+NonPrime[n+1]]; // _Bruno Berselli_, Apr 05 2014
%o A167611 (Python)
%o A167611 from sympy import isprime, composite
%o A167611 print([1] + [totest for k in range(1,91) if not isprime(totest := composite(k) + composite(k+1))]) # _Karl-Heinz Hofmann_, Jan 25 2024
%Y A167611 Cf. A018252, A141468, A151740.
%K A167611 nonn
%O A167611 1,2
%A A167611 _Juri-Stepan Gerasimov_, Nov 07 2009
%E A167611 Entries confirmed by _R. J. Mathar_, May 30 2010