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A195118 Numbers with largest and smallest prime factors differing by 6. 4
55, 91, 187, 247, 275, 385, 391, 605, 637, 667, 1001, 1147, 1183, 1375, 1591, 1925, 1927, 2057, 2431, 2491, 2695, 3025, 3127, 3179, 3211, 4087, 4199, 4235, 4459, 4693, 4891, 5767, 6647, 6655, 6875, 7007, 7387, 7429, 8281, 8993, 9625, 9991, 10807, 11011 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..250

Eric Weisstein's World of Mathematics, Sexy Primes

EXAMPLE

a(10) = 667 = 23 * 29;

a(11) = 1001 = 7 * 11 * 13;

a(12) = 1147 = 31 * 37;

a(13) = 1183 = 7 * 13^2.

PROG

(Haskell)

a195118 n = a195118_list !! (n-1)

a195118_list = filter f [3, 5..] where

   f x = last pfs - head pfs == 6 where pfs = a027748_row x

CROSSREFS

Cf. A195106, A111192; A143205 is a subsequence.

Sequence in context: A230125 A027865 A247681 * A143205 A111192 A063873

Adjacent sequences:  A195115 A195116 A195117 * A195119 A195120 A195121

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Sep 13 2011

STATUS

approved

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Last modified June 25 11:55 EDT 2017. Contains 288710 sequences.