A081653 Greatest common divisor of sums of decimal digits of n and of n-th prime.

1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 4, 1, 1, 1, 2, 1, 2, 1, 1, 2, 5, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 7, 1, 1, 2, 11, 1, 1, 2, 1, 1, 2, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 16, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 5, 1

Offset

1,6

Links

Table of n, a(n) for n=1..105.

Formula

a(n) = GCD(A007953(n), A007605(n)).

Example

a(8) = GCD(A007953(8), A007953(A000040(8))) = GCD(8, A007953(19)) = GCD(8,1+9) = GCD(4*2,5*2) = 2.

Mathematica

A081653[n_Integer]:=GCD[Plus@@IntegerDigits[n], Plus@@IntegerDigits[Prime[n]]]; Table[A081653[n], {n, 105}] (* Enrique Pérez Herrero, Aug 07 2010 *)

Crossrefs

Cf. A000040, A007953, A007605, A081652, A066750.

Sequence in context: A263835 A113310 A359537 * A249615 A096860 A128185

Adjacent sequences: A081650 A081651 A081652 * A081654 A081655 A081656

Keyword

nonn,base,easy

Author

Reinhard Zumkeller, Mar 25 2003

Status

approved