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%I #7 Dec 18 2017 11:57:12
%S 0,0,0,0,0,1,0,0,0,0,0,1,0,0,1,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,
%T 1,1,0,0,0,0,0,1,0,0,1,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,
%U 0,1,0,1,0,0,1,0,1,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,1
%N Characteristic function for A104210: a(n) = 1 if n is divisible by at least 2 consecutive primes, 0 otherwise.
%H Antti Karttunen, <a href="/A296210/b296210.txt">Table of n, a(n) for n = 1..65537</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%t Array[Boole@ MemberQ[Differences@ PrimePi@ FactorInteger[#][[All, 1]], 1] &, 105] (* _Michael De Vlieger_, Dec 16 2017 *)
%o (PARI) A296210(n) = { if(1==n,return(0)); my(ps=factor(n)[,1], pis=vector(length(ps),i,primepi(ps[i])), diffsminusones = vector(length(pis)-1,i,(pis[i+1]-pis[i])-1)); !factorback(diffsminusones); };
%Y Cf. A104210, A166469, A192280.
%K nonn
%O 1
%A _Antti Karttunen_, Dec 15 2017