A238161 Greatest common divisor of the prime factors of n, each increased by 1.

3, 4, 3, 6, 1, 8, 3, 4, 3, 12, 1, 14, 1, 2, 3, 18, 1, 20, 3, 4, 3, 24, 1, 6, 1, 4, 1, 30, 1, 32, 3, 4, 3, 2, 1, 38, 1, 2, 3, 42, 1, 44, 3, 2, 3, 48, 1, 8, 3, 2, 1, 54, 1, 6, 1, 4, 3, 60, 1, 62, 1, 4, 3, 2, 1, 68, 3, 4, 1, 72, 1, 74, 1, 2, 1, 4, 1, 80, 3, 4, 3, 84, 1, 6, 1, 2, 3, 90, 1, 2, 3, 4, 3, 2, 1, 98, 1, 4, 3

Offset: 2

Author

Joseph L. Pe, Feb 18 2014

Keywords

• nonn
• easy

Examples

			10 has prime factors 2 and 5, which become 3 and 6 when respectively increased by 1, and gcd(3, 6) = 3. Therefore, a(10) = 3.
		

Programs

Mathematica

Table[Apply[GCD, (Transpose[FactorInteger[n]][[1]] + 1)], {n, 2, 100}]