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A039789 phi(n) is equal to the product of (the sum of prime factors and the sum of exponents) of n+1. 0
7, 15, 62, 65, 76, 98, 260, 980 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

No further terms up to 20,000,000. - Harvey P. Dale, Apr 19 2013

LINKS

Table of n, a(n) for n=1..8.

EXAMPLE

phi(62)=30, 63=3^2*7^1, (3+7)*(2+1)=30.

MATHEMATICA

epQ[n_]:=Module[{fi=Transpose[FactorInteger[n+1]]}, EulerPhi[n]== Total[ First[fi]]* Total[Last[fi]]]; Select[Range[1000], epQ] (* Harvey P. Dale, Apr 19 2013 *)

CROSSREFS

Cf. A000010, A039697.

Sequence in context: A141548 A146159 A187986 * A279882 A171064 A042313

Adjacent sequences:  A039786 A039787 A039788 * A039790 A039791 A039792

KEYWORD

nonn

AUTHOR

Olivier Gérard

EXTENSIONS

Next term if it exists is greater than 1500000 - Reiner Martin (reinermartin(AT)hotmail.com), May 20 2001

STATUS

approved

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Last modified September 23 09:03 EDT 2020. Contains 337298 sequences. (Running on oeis4.)