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A089281 Smallest prime factor of floor(Pi*10^n). 4
3, 31, 2, 3, 5, 314159, 2, 2, 3, 3, 5, 2, 13, 163, 43, 13, 2, 317213509, 2, 2, 2, 2, 2, 2, 83, 41, 2, 3, 2, 3, 3, 5, 2, 2, 2, 2, 2, 31415926535897932384626433832795028841, 13, 59, 3, 2, 3, 3, 3, 3, 3, 31, 3, 1657, 2, 3, 2, 2, 2, 29, 13, 2, 3, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Ryan Moore, Table of n, a(n) for n = 0..100 (first 60 terms from Ray Chandler)

FORMULA

a(n) = A020639(A011545(n)).

EXAMPLE

n=10: floor(Pi*10^10)=31415926535=5*7*31*28954771: a(10)=5.

PROG

(PARI) a(n) = factor(floor(Pi*10^n))[1, 1]; \\ Michel Marcus, Dec 28 2013

CROSSREFS

Cf. A078604, A000796.

Sequence in context: A068698 A053300 A322777 * A212729 A218357 A090543

Adjacent sequences: A089278 A089279 A089280 * A089282 A089283 A089284

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Oct 30 2003

EXTENSIONS

More terms from Ray Chandler, Oct 30 2003

More terms from Ryan Moore, Dec 27 2013

STATUS

approved

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Last modified November 27 13:59 EST 2022. Contains 358405 sequences. (Running on oeis4.)