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A111671 Smallest prime p > 3 such that p-1 has a prime factor > (p-1)^(n/(n+1)). 0
7, 11, 23, 47, 83, 167, 263, 563, 1187, 2063, 4127, 8423, 16487, 32843, 65543, 131267, 262643, 524387, 1048703, 2097779, 4195259, 8389163, 16777907, 33554519, 67109543, 134217827, 268436867 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(1) = 7 = A111668(1). Conjectures: (1) This is a subsequence of the safe primes (A005385), (2) lim{n --> oo}(a(n+1)/a(n)) = 2.

LINKS

Table of n, a(n) for n=1..27.

CROSSREFS

Cf. A111668, A005385 (safe primes).

Sequence in context: A079138 A319135 A163848 * A213895 A140111 A118072

Adjacent sequences:  A111668 A111669 A111670 * A111672 A111673 A111674

KEYWORD

nonn

AUTHOR

Rick L. Shepherd, Aug 15 2005

STATUS

approved

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Last modified February 25 22:55 EST 2020. Contains 332270 sequences. (Running on oeis4.)