OFFSET
1,5
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
MAPLE
a := n -> nops(numtheory:-factorset(binomial(2*n, n)) minus select(isprime, {$n+1..2*n})): seq(a(n), n=1..82); # Peter Luschny, Oct 31 2015
MATHEMATICA
Table[Length[Select[Transpose[FactorInteger[Binomial[2 n, n]]][[1]], # <= n &]], {n, 100}]
PROG
(PARI) valp(n, p)=my(s); while(n\=p, s+=n); s
a(n)=my(s); forprime(p=2, n, if(valp(2*n, p)>2*valp(n, p), s++)); s \\ Charles R Greathouse IV, May 25 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Aug 17 2011
STATUS
approved