OFFSET
1,1
EXAMPLE
a(1)=6 because each number that is 7 or larger can be written as the sum of distinct primes.
a(2)=23 because the squarefree numbers less than or equal to 23 that are the product of two primes are {6, 10, 14, 15, 21, 22} and there is no way to add some subset of these together to get 23; on the other hand every number greater than 23 can be so represented, i.e., 24=10+14, 25=10+15, 26=26, 27=6+21, 28=6+22, 30=6+10+14, and so on.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Steve Butler, Feb 20 2015
STATUS
approved