OFFSET
1,1
FORMULA
a(n)=y*(smallest prime that is larger than y), where y is the product of first n-1 consecutive primes.
a(n) = (n-1)# * NextPrime((n-1)#). a(n) = A002110(n-1) * NextPrime(A002110(n-1)). E.g. a(15) = 14# * 13082761331670077 = (2 * 3 * 5 * 7 * 11 * 13 * 17 * 19 * 23 * 29 * 31 * 37 * 41 * 43) + 13082761331670077, since 13082761331670077 = 14# + 47 is the least prime > 14#. - Jonathan Vos Post, Feb 13 2006
EXAMPLE
a(3)=42; indeed, 42=2*3*7, 7>sqrt(42) and 2*3*5 does not qualify because
5<sqrt(30).
MAPLE
a:=n->product(ithprime(j), j=1..n-1)*nextprime(product(ithprime(j), j=1..n-1)): seq(a(n), n=1..16);
CROSSREFS
KEYWORD
nonn
AUTHOR
Emeric Deutsch, Feb 02 2006
STATUS
approved