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A081653 Greatest common divisor of sums of decimal digits of n and of n-th prime. 2
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 (list; graph; refs; listen; history; internal format)
OFFSET

1,6

COMMENTS

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]]]; [From Enrique Perez Herrero (psychgeometry(AT)gmail.com), Aug 07 2010]

CROSSREFS

Cf. A000040, A081652, A066750.

Sequence in context: A061916 A076348 A113310 * A096860 A128185 A175244

Adjacent sequences:  A081650 A081651 A081652 * A081654 A081655 A081656

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 25 2003

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Last modified February 14 20:38 EST 2012. Contains 205663 sequences.