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

1,2

COMMENTS

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

No further terms up to 10^26. - Chai Wah Wu, Nov 28 2015

LINKS

Table of n, a(n) for n=1..4.

EXAMPLE

12 = 4*3 = sigma(1+2)*sigma(1*2).

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: A283627 A013862 A116233 * A175906 A144546 A165970

Adjacent sequences:  A145742 A145743 A145744 * A145746 A145747 A145748

KEYWORD

base,more,nonn

AUTHOR

Farideh Firoozbakht, Oct 26 2008

STATUS

approved

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Last modified September 21 05:02 EDT 2021. Contains 347596 sequences. (Running on oeis4.)