A117366 a(n) = smallest prime greater than the largest prime dividing n.

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

Offset

1,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Formula

a(n) = A151800(A006530(n)). - Reinhard Zumkeller, Apr 06 2015

a(n) = A000040(A159081(n)). - Antti Karttunen, Jan 15 2020

Example

5 is the largest prime dividing 10. So a(10) is the smallest prime > 5, which is 7.

Mathematica

Table[Prime[PrimePi[FactorInteger[n][[Length[FactorInteger[n]]]][[1]]]+1], {n, 2, 80}], 2, 1] (* Stefan Steinerberger, Apr 09 2006 *)

Prog

(Haskell)
a117366 = a151800 . a006530  -- Reinhard Zumkeller, Apr 06 2015
(PARI) A117366(n) = if(1==n, 2, nextprime(1+vecmax(factor(n)[, 1]))); \\ Antti Karttunen, Jan 15 2020

Crossrefs

Cf. A117364, A117365, A117367.

Cf. A000040, A006530, A151800, A159081.

Sequence in context: A052248 A092386 A117369 * A341643 A073482 A318411

Adjacent sequences: A117363 A117364 A117365 * A117367 A117368 A117369

Keyword

nonn

Author

Leroy Quet, Mar 10 2006

Extensions

More terms from Stefan Steinerberger, Apr 09 2006

Status

approved