A242744 Least number k > 2 such that (k!-n)/(k-n) is an integer.

3, 4, 3, 4, 3, 6, 4, 4, 5, 10, 6, 6, 4, 10, 8, 16, 9, 18, 6, 10, 11, 6, 4, 12, 13, 6, 5, 12, 15, 30, 9, 16, 17, 12, 18, 18, 12, 26, 6, 40, 21, 42, 22, 22, 12, 16, 6, 42, 16, 12, 26, 52, 27, 44, 18, 6, 12, 58, 30, 30, 31, 12, 12, 10, 33, 66, 22, 16, 35, 70, 36, 36, 37, 18, 38, 66, 9, 78, 12, 12, 41, 82, 16, 42, 28, 58, 44, 30, 12, 18, 30, 46

Offset

2,1

Comments

For n > 4, a(2n+1) <= 2n and a(2n) <= n.

Links

Jinyuan Wang, Table of n, a(n) for n = 2..1000

Example

(6!-3)/(6-3) = 717/3 = 239 is an integer. Thus a(6) = 3.

Prog

(PARI) a(n) = if(n==3, 4, for(k=3, oo, if((k!-n)%(k-n)==0, return(k)))); \\ Modified by Jinyuan Wang, Mar 13 2020

Crossrefs

Sequence in context: A010702 A345439 A095925 * A066783 A046536 A052384

Adjacent sequences: A242741 A242742 A242743 * A242745 A242746 A242747

Keyword

nonn

Author

Derek Orr, May 21 2014

Status

approved