A117367 a(n) = smallest prime greater than the smallest prime dividing n.

2, 3, 5, 3, 7, 3, 11, 3, 5, 3, 13, 3, 17, 3, 5, 3, 19, 3, 23, 3, 5, 3, 29, 3, 7, 3, 5, 3, 31, 3, 37, 3, 5, 3, 7, 3, 41, 3, 5, 3, 43, 3, 47, 3, 5, 3, 53, 3, 11, 3, 5, 3, 59, 3, 7, 3, 5, 3, 61, 3, 67, 3, 5, 3, 7, 3, 71, 3, 5, 3, 73, 3, 79, 3, 5, 3, 11, 3, 83, 3, 5, 3, 89, 3, 7, 3, 5, 3, 97, 3, 11, 3, 5

Offset: 1

Author

Leroy Quet, Mar 10 2006

Keywords

• nonn

Comments

All even-indexed terms are 3.

Examples

			5 is the smallest prime dividing 35. So a(35) is the smallest prime > 5, which is 7.
		

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A117364, A117365, A117366.

Programs

Maple

with(numtheory): a:=proc(n): if n=1 then 2 else nextprime(factorset(n)[1]) fi: end: seq(a(n),n=1..100); # Emeric Deutsch, Apr 22 2006

Mathematica

Table[NextPrime[FactorInteger[n][[1, 1]]], {n, 93}] (* Michael De Vlieger, Sep 16 2017 *)

Extensions

More terms from Emeric Deutsch, Apr 22 2006