OFFSET
1,2
COMMENTS
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..100000
FORMULA
For n <= 5, a(n) = n, for >= 5, a(n) = 5 when n is a prime, and a(n) = 3+n-A000720(n) when n is a composite.
PROG
(PARI) A305900(n) = if(n<=5, n, if(isprime(n), 5, 3+n-primepi(n)));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 14 2018
STATUS
approved