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 A143958 Integers n > 1 such that n-1 is divisible by the difference between the largest and smallest primes dividing n. 4
 6, 10, 12, 15, 18, 21, 24, 33, 35, 36, 40, 45, 48, 54, 55, 56, 65, 72, 75, 77, 78, 85, 91, 96, 100, 105, 108, 126, 133, 135, 136, 143, 144, 145, 154, 160, 161, 162, 175, 187, 189, 192, 196, 209, 216, 217, 221, 225, 245, 247, 250, 253, 261, 288, 297, 323, 324, 336 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS If p is prime, (p+t)*p is in the sequence if t is a divisor of p^2-1 such that p+t is prime. - Robert Israel, Nov 27 2017 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE The largest prime dividing 21 is 7. The smallest prime dividing 21 is 3. 7-3 = 4 divides 21-1 = 20. So 21 is in the sequence. MAPLE filter:= proc(n) local F;   F:= [min, max](numtheory:-factorset(n));   F[1]

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Last modified May 31 18:16 EDT 2020. Contains 334748 sequences. (Running on oeis4.)