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A145745 Numbers n such that n=sigma(sum of digits of n)*sigma(product of digits of n). +0
1
1, 12, 6266169, 6931848 (list; graph; listen)
OFFSET

1,2

COMMENT

There is no further term up to 2*10^9.

EXAMPLE

6931848=56*123783=sigma(6+9+3+1+8+4+8)*sigma(6*9*3*1*8*4*8).

MATHEMATICA

Do[h=IntegerDigits[n]; s=Apply[Plus, h]; p=Apply[Times, h]; If[n== DivisorSigma[1, s]*DivisorSigma[1, p], Print[n]], {n, 2000000000}]

CROSSREFS

Cf. A038369.

Sequence in context: A159951 A013862 A116233 this_sequence A144546 A165970 A081357

Adjacent sequences: A145742 A145743 A145744 this_sequence A145746 A145747 A145748

KEYWORD

base,more,nonn

AUTHOR

Farideh Firoozbakht (mymontain(AT)yahoo.com), Oct 26 2008

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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