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

1,1

Comments

All even-indexed terms are 3.

Links

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

Example

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

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 *)

Crossrefs

Cf. A117364, A117365, A117366.

Sequence in context: A147593 A108396 A239476 * A080184 A052248 A092386

Adjacent sequences: A117364 A117365 A117366 * A117368 A117369 A117370

Keyword

nonn

Author

Leroy Quet, Mar 10 2006

Extensions

More terms from Emeric Deutsch, Apr 22 2006

Status

approved