A085275 Sum of n-th composite number and its largest prime divisor.

6, 9, 10, 12, 15, 15, 21, 20, 18, 21, 25, 28, 33, 27, 30, 39, 30, 35, 35, 34, 44, 51, 42, 39, 57, 52, 45, 49, 55, 50, 69, 51, 56, 55, 68, 65, 57, 66, 63, 76, 87, 65, 93, 70, 66, 78, 77, 85, 92, 77, 75, 111, 80, 95, 88, 91, 85, 84, 123, 91, 102, 129, 116, 99, 95, 104, 115, 124

Offset: 4

Author

Cino Hilliard, Aug 12 2003

Keywords

• easy
• nonn

Examples

			For 91=7*13 we have 91+13 = 104; for 92=2*2*23 we have 92+23 = 115.
		

Crossrefs

Cf. A085271, A085273.

Programs

PARI

cminusp3(n) = { for(x=2,n, forstep(p=x,2,-1, if(isprime(p) & x%p==0 & isprime(x)==0, print1(x+p,","); break); ) ) }