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A060210 Largest prime factor of 1+smaller term of twin primes. 6
2, 3, 3, 3, 5, 7, 5, 3, 17, 3, 23, 5, 5, 3, 11, 19, 5, 5, 47, 13, 29, 7, 3, 11, 29, 19, 5, 103, 107, 11, 5, 137, 23, 13, 7, 17, 43, 7, 59, 13, 3, 41, 71, 43, 31, 11, 17, 11, 19, 31, 67, 5, 139, 283, 41, 149, 13, 313, 23, 13, 37, 13, 347, 29, 11, 71, 17, 373, 7, 11, 13, 397, 17 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Also: Largest prime factor of the average, or the sum, of twin prime pairs. - M. F. Hasler, Jan 03 2011

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

EXAMPLE

101 is the 9th lesser-twin,102=2.3.17, its max p factor is 17=a(9).

MATHEMATICA

FactorInteger[1+#][[-1, 1]]&/@Select[Partition[Prime[Range[500]], 2, 1], #[[2]]- #[[1]]==2&][[All, 1]] (* Harvey P. Dale, Jan 16 2017 *)

PROG

(PARI) p=3; for(n=1, 1e3, until(o+2==p, p=nextprime(2+o=p)); print1(vecmax(factor(p-1)[, 1])", "))  \\ - M. F. Hasler, Jan 03 2011

CROSSREFS

Cf. A001359, A001454, A002822, A059960, A027856.

Sequence in context: A029065 A263253 A162157 * A260460 A000025 A036020

Adjacent sequences:  A060207 A060208 A060209 * A060211 A060212 A060213

KEYWORD

nonn

AUTHOR

Labos Elemer, Mar 20 2001

STATUS

approved

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Last modified November 18 10:38 EST 2017. Contains 294887 sequences.