OFFSET
1,2
FORMULA
a(n) = primepi(A138000(n)).
PROG
(PARI) {s=1; p=0; for( n=1, 20, until( !bitand( s, s>>prime(p++) ), ); s+=s<<prime(p); print1( p, ", "))}
CROSSREFS
KEYWORD
nonn
AUTHOR
M. F. Hasler, Apr 10 2008
EXTENSIONS
a(22)-a(30) from Donovan Johnson, Oct 03 2009
a(31)-a(36) from Amiram Eldar, Sep 06 2024
STATUS
approved