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%I #15 Jan 21 2020 10:22:49
%S 0,20,24,31,34,36,41,48,50,54,57,69,71,79,86,88,89,92,97,104,106,111,
%T 116,119,130,132,134,136,139,141,145,149,150,154,160,167,171,174,176,
%U 179,180,189,190,191,193,196,201,207,209,211,212,219,222,223,224,225
%N Nonnegative numbers k such that neither 6*k+-1 is prime.
%C A060461 is the main sequence for this entry.
%C Numbers k such that 6*k-1 and 6*k+1 are twin nonprimes.
%H Amiram Eldar, <a href="/A171696/b171696.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n+1) = A060461(n).
%F a(n) = n + O(n/log n). - _Charles R Greathouse IV_, Feb 17 2017
%p isA171696 := proc(n) not isprime(6*n+1) and not isprime(6*n-1) ; end proc: for n from 0 to 300 do if isA171696(n) then printf("%d,",n) ; end if; end do: # _R. J. Mathar_, Mar 18 2010
%t Select[Range[0, 225], !Or @@ PrimeQ[6# + {-1, 1}] &] (* _Amiram Eldar_, Jan 21 2020 *)
%o (PARI) is(n)=!isprime(6*n-1) && !isprime(6*n+1) \\ _Charles R Greathouse IV_, Feb 17 2017
%Y Cf. A001477, A060461.
%K nonn
%O 1,2
%A _Juri-Stepan Gerasimov_, Dec 15 2009
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