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A076606 Min { largest prime factor of n-1, largest prime factor of n+1 }. 0
2, 3, 2, 5, 2, 3, 2, 3, 3, 11, 3, 5, 2, 5, 2, 17, 3, 7, 5, 7, 3, 5, 3, 3, 7, 3, 5, 29, 2, 11, 2, 7, 3, 7, 3, 13, 5, 13, 5, 41, 7, 5, 11, 5, 3, 7, 3, 7, 5, 17, 3, 11, 3, 11, 7, 19, 5, 59, 5, 7, 2, 7, 2, 13, 11, 23, 7, 23, 3, 71, 3, 5, 19, 5, 13, 11, 5, 3, 5, 3, 7, 17, 7, 17, 11, 29, 5, 13, 5, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

LINKS

Table of n, a(n) for n=3..92.

EXAMPLE

a[11]=3, as 3 is the smallest prime factor from 10=2.5 and 12=2.2.3

PROG

(PARI) for (n=3, 100, print1(", "min(factor(n-1)[, 1][length(factor(n-1)[, 1])], factor(n+1)[, 1][length(factor(n+1)[, 1])])))

CROSSREFS

Sequence in context: A262597 A217607 A066727 * A056927 A094290 A265111

Adjacent sequences:  A076603 A076604 A076605 * A076607 A076608 A076609

KEYWORD

nonn

AUTHOR

Jon Perry, Oct 21 2002

STATUS

approved

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Last modified December 1 16:07 EST 2021. Contains 349430 sequences. (Running on oeis4.)