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A096737 a(1) = 2; for n>1: a(n) = integer part of y-value when x=0 in (y-tau(n))/(x-1)=(1-tau(n))/(n-1), tau=A000005. 2
2, 3, 2, 3, 2, 4, 2, 4, 3, 4, 2, 6, 2, 4, 4, 5, 2, 6, 2, 6, 4, 4, 2, 8, 3, 4, 4, 6, 2, 8, 2, 6, 4, 4, 4, 9, 2, 4, 4, 8, 2, 8, 2, 6, 6, 4, 2, 10, 3, 6, 4, 6, 2, 8, 4, 8, 4, 4, 2, 12, 2, 4, 6, 7, 4, 8, 2, 6, 4, 8, 2, 12, 2, 4, 6, 6, 4, 8, 2, 10, 5, 4, 2, 12, 4, 4, 4, 8, 2, 12, 4, 6, 4, 4, 4, 12, 2, 6, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) = 2 iff n is prime.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = floor((n*tau(n)-1)/(n-1))for n>1, a(1) = 2.

a(1)=2, a(2)=3, a(n)=tau(n) if n>2. - Michael Somos, Sep 03 2006

EXAMPLE

See A096736.

MATHEMATICA

Join[{2, 3}, Table[Floor[(n*DivisorSigma[0, n] - 1)/(n - 1)], {n, 3, 100}]] (* G. C. Greubel, Nov 27 2016 *)

CROSSREFS

Cf. A096736.

Sequence in context: A245575 A333600 A339625 * A304535 A241856 A278354

Adjacent sequences:  A096734 A096735 A096736 * A096738 A096739 A096740

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 06 2004

STATUS

approved

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Last modified August 11 00:55 EDT 2022. Contains 356046 sequences. (Running on oeis4.)