A086936 Number of primes between n and p(n) inclusive.

1, 2, 2, 2, 3, 3, 4, 4, 5, 6, 7, 7, 8, 8, 9, 10, 11, 11, 12, 12, 13, 14, 15, 15, 16, 17, 18, 19, 20, 20, 21, 21, 22, 23, 24, 25, 26, 26, 27, 28, 29, 29, 30, 30, 31, 32, 33, 33, 34, 35, 36, 37, 38, 38, 39, 40, 41, 42, 43, 43, 44, 44, 45, 46, 47, 48, 49, 49, 50, 51, 52, 52, 53, 53

Offset

1,2

Comments

Or number of nonprimes A141468<n. [From Juri-Stepan Gerasimov, Nov 19 2009]

Links

Table of n, a(n) for n=1..74.

Formula

a(n)=sum{k=0..n, (1+mu(if(prime(k), k, 1)))/2} [offset 0] - Paul Barry, May 10 2005

a(n)=1+n-A000720(n). [From Juri-Stepan Gerasimov, Nov 19 2009]

Crossrefs

Cf. A000027, A000720, A141468. [From Juri-Stepan Gerasimov, Nov 19 2009]

Sequence in context: A035429 A280169 A018117 * A214129 A280151 A094990

Adjacent sequences: A086933 A086934 A086935 * A086937 A086938 A086939

Keyword

easy,nonn

Author

Zak Seidov, Sep 22 2003

Status

approved