%I #10 Feb 04 2019 02:12:39
%S 0,17,19,29,31,41,43,49,51,53,55,65,67,69,71,77,79,89,91,97,99,101,
%T 103,109,111,113,115,125,127,129,131,137,139,149,151,153,155,161,163,
%U 169,171,173,175,181,183,185,187,189,191,197,199,209,211,221,223,229,231
%N Numbers k such that neither k-1 nor k+1 is prime or semiprime.
%C a(n+1) is the (n+2)-th odd sum of two consecutive nonnegative nonprimes.
%H Harvey P. Dale, <a href="/A176462/b176462.txt">Table of n, a(n) for n = 1..2000</a>
%F a(n+1) = A166685(n+2).
%e 0 is a term because neither 0-1=-1 nor 0+1=1 is prime or semiprime.
%p isA001358 := proc(n) numtheory[bigomega](n) = 2 ; end proc: for n from 0 to 400 do if isA001358(n+1) or isA001358(n-1) or isprime(n+1) or isprime(n-1) then ; else printf("%d,",n) ; end if; end do: # _R. J. Mathar_, Apr 20 2010
%t Join[{0},Flatten[Position[Partition[Table[If[PrimeQ[n]||PrimeOmega[n] == 2,1,0],{n,250}],3,1],_?(#[[1]]==#[[3]]==0&),{1},Heads -> False]]+ 1] (* _Harvey P. Dale_, Oct 27 2015 *)
%Y Cf. A141468.
%K nonn
%O 1,2
%A _Juri-Stepan Gerasimov_, Apr 18 2010
%E Entries checked by _R. J. Mathar_, Apr 20 2010