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%I #19 Nov 30 2016 13:11:39
%S 34,86,94,122,142,171,202,214,218,245,285,302,394,429,435,446,507,603,
%T 604,605,634,638,698,842,922,963,1042,1075,1084,1085,1131,1138,1245,
%U 1262,1275,1310,1346,1402,1413,1431,1435,1449,1491,1533,1557,1587,1605,1635,1642,1676,1762,1772,1838,1886,1894,1925,1942
%N Numbers n such that n-1 and n+1 have the same number of prime factors as n (with multiplicity).
%H Ely Golden, <a href="/A278311/b278311.txt">Table of n, a(n) for n = 1..10000</a>
%e a(1) = 34, as 33, 34, and 35 all have 2 prime factors.
%e a(2) = 86, as 85, 86, and 87 all have 2 prime factors.
%o (Java) public class A278311{
%o public static void main(String[] args)throws Exception{
%o long dim0=numberOfPrimeFactors(2);//note that this method must be manually implemented by the user
%o long dim1=numberOfPrimeFactors(3);
%o long dim2;
%o long counter=4;
%o long index=1;
%o while(index<=10000){
%o dim2=numberOfPrimeFactors(counter);
%o if(dim2==dim1&&dim1==dim0){System.out.println(index+" "+(counter-1));index++;}
%o dim0=dim1;
%o dim1=dim2;
%o counter++;
%o }
%o }
%o }
%o (SageMath)
%o def bigomega(x):
%o s=0;
%o f=list(factor(x));
%o for c in range(len(f)):
%o s+=f[c][1]
%o return s;
%o dim0=bigomega(2);
%o dim1=bigomega(3);
%o counter=4
%o index=1
%o while(index<=10000):
%o dim2=bigomega(counter);
%o if(dim2==dim1&dim1==dim0):
%o print(str(index)+" "+str(counter-1))
%o index+=1;
%o dim0=dim1;
%o dim1=dim2;
%o counter+=1;
%o (PARI) isok(n) = (bigomega(n-1) == bigomega(n)) && (bigomega(n) == bigomega(n+1)); \\ _Michel Marcus_, Nov 17 2016
%Y Intersection of A045920 and A278291.
%Y a(n) = A045939(n) + 1.
%K nonn
%O 1,1
%A _Ely Golden_, Nov 17 2016
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