A136801 Largest prime factor of the composites in the n-th prime gap larger than 2.

5, 7, 11, 13, 17, 19, 23, 17, 29, 31, 23, 37, 41, 43, 47, 11, 53, 37, 61, 43, 67, 73, 31, 79, 83, 43, 89, 61, 97, 103, 109, 113, 29, 79, 83, 127, 131, 89, 137, 139, 97, 151, 103, 157, 163, 167, 173, 13, 179, 181, 53, 47, 191, 193, 197, 199, 101, 139, 211, 109, 17, 223

Offset

1,1

Comments

The largest prime factor of numbers in the interval [A136798(n),A136799(n)].

The sequence is obtained from A052248 by removing terms from composites in prime gaps of size 2.

Links

Table of n, a(n) for n=1..62.

Example

a(1)=5 because the composites in the run from 8, 9, 10 contain prime factors 2, 3, and 5, with 5 being the largest at N=10.

Maple

A006530 := proc(n) max( op(numtheory[factorset](n))) ; end:
A136798 := proc(n) local a; if n = 1 then 8; else a := nextprime( procname(n-1))+1 ; while nextprime(a)-a <=2 do a := nextprime(a)+1 ; od; RETURN(a) ; fi; end:
A136801 := proc(n) local a, i; i := A136798(n) ; a := A006530( i) ; while not isprime(i+1) do i := i+1 ; a := max(a, A006530(i)) ; od: a ; end:
seq(A136801(n), n=1..20) ; # R. J. Mathar, May 27 2009

Crossrefs

Cf. A136798, A136799, A136800, A136802.

Sequence in context: A272260 A322271 A306289 * A106571 A067291 A286265

Adjacent sequences: A136798 A136799 A136800 * A136802 A136803 A136804

Keyword

easy,nonn

Author

Enoch Haga, Jan 24 2008

Extensions

Edited by R. J. Mathar, May 27 2009

Status

approved