A083721 Number of primes greater than the greatest prime factor of n but not greater than n.
0, 0, 0, 1, 0, 1, 0, 3, 2, 1, 0, 3, 0, 2, 3, 5, 0, 5, 0, 5, 4, 3, 0, 7, 6, 3, 7, 5, 0, 7, 0, 10, 6, 4, 7, 9, 0, 4, 6, 9, 0, 9, 0, 9, 11, 5, 0, 13, 11, 12, 8, 9, 0, 14, 11, 12, 8, 6, 0, 14, 0, 7, 14, 17, 12, 13, 0, 12, 10, 15, 0, 18, 0, 9, 18, 13, 16, 15, 0, 19, 20, 9, 0, 19, 16, 9, 13, 18, 0, 21, 18
Offset: 1
Keywords
Programs
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PARI
a(n)=if(n>3,my(f=factor(n)[,1]);primepi(n)-primepi(f[#f]),0) \\ Charles R Greathouse IV, Feb 21 2013
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