A081652 Greatest common divisor of n and sum of decimal digits of n-th prime.

1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 7, 1, 8, 1, 1, 1, 4, 1, 2, 1, 1, 1, 2, 1, 4, 1, 5, 1, 1, 11, 1, 7, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 11, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 8, 1, 1, 1, 4, 1, 2, 1, 8, 1, 2, 1, 10, 1, 17, 1, 4

Offset: 1

Author

Reinhard Zumkeller, Mar 25 2003

Keywords

• nonn
• base
• easy

Examples

			a(16) = GCD(16, A007953(A000040(16))) = GCD(16, A007953(53)) = GCD(16,5+3) = GCD(8*2,8) = 8.
		

Crossrefs

Cf. A000040, A007953, A081653, A066750.

Programs

Mathematica

Table[GCD[n,Total[IntegerDigits[Prime[n]]]],{n,110}] (* Harvey P. Dale, Jul 12 2012 *)

Formula

a(n) = GCD(n, A007605(n)).