OFFSET
0,1
COMMENTS
Number of nonzero bits in A098591(n).
The number a(n) is < 8 except for n=0. - Pierre CAMI, Jun 02 2009
For references to positions where a(n) = 7 and related explanation, see A100418. - Peter Munn, Sep 06 2023
LINKS
Dennis Martin, Proofs Regarding Primorial Patterns [Cached copy, with permission of the author].
Hugo Pfoertner, Patterns count table.
EXAMPLE
a(1)=7 because there are 7 primes in the interval (30,60): 31,37,41,43,47,53,59.
a(26)=3 because the interval of length 30 following 26*30=780 contains 3 primes: 787, 797 and 809.
PROG
(FORTRAN) See links given in A098591.
(PARI) a(n) = primepi(30*(n+1)) - primepi(30*n); \\ Michel Marcus, Apr 04 2020
(Python)
from sympy import primerange
def a(n): return len(list(primerange(n*30, (n+1)*30)))
print([a(n) for n in range(106)]) # Michael S. Branicky, Oct 07 2021
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Hugo Pfoertner, Sep 16 2004
EXTENSIONS
Edited by N. J. A. Sloane, Jun 12 2009 at the suggestion of R. J. Mathar
STATUS
approved