A082867 Numbers n such that there exists a proper divisor 1 < m < n where m divides n and m+1 divides n+1, but there is no divisor d such that d divides n, d+1 divides n+1 and d+2 divides n+2.

8, 15, 20, 24, 27, 32, 35, 39, 44, 48, 51, 56, 65, 68, 75, 80, 84, 87, 90, 92, 95, 99, 104, 111, 116, 119, 120, 125, 128, 132, 135, 140, 143, 144, 147, 152, 155, 159, 164, 168, 171, 175, 176, 185, 188, 189, 195, 200, 204, 207, 212, 216, 219, 224, 231, 236, 245

Offset: 1

Author

Anne M. Donovan (anned3005(AT)aol.com), May 24 2003

Keywords

• easy
• nonn

Examples

			8 is a member because 2 divides 8, 3 divides 9 (and 4 does not divide 10).
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A082772.

Programs

PARI

is(n)=my(t); fordiv(n,m, if(m==1, next); if((n+1)%(m+1)==0, if(m==n, return(t)); t=1; if((n+2)%(m+2)==0, return(0)))) \\ Charles R Greathouse IV, Jul 05 2022

Extensions

Corrected by T. D. Noe, Oct 25 2006