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A163619
Let q(p) be the smallest prime greater than the prime p. A positive integer n is included in this sequence if n+1 is divisible by q(p) for each prime p dividing n.
0
2, 8, 9, 20, 32, 98, 125, 128, 169, 464, 512, 729, 961, 1280, 2048, 2108, 5252, 8000, 8192, 9728, 15872, 16807, 18176, 22385, 32768, 36992, 50000, 53792, 59049, 78821, 81920, 97556, 98125, 100352, 124659, 131072, 195129, 219488, 223040, 307328
OFFSET
1,1
COMMENTS
All terms of this sequence are in sequence A073606.
EXAMPLE
20 is divisible by the primes 2 and 5. q(2) = 3, and q(5)=7. 20+1 = 21 is divisible by both 3 and 7, so 20 is in this sequence.
MATHEMATICA
depQ[n_]:=With[{c=NextPrime[FactorInteger[n][[;; , 1]]]}, AllTrue[(n+1)/c, IntegerQ]]; Select[Range[ 2, 350000], depQ] (* Harvey P. Dale, Jun 10 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Aug 01 2009
EXTENSIONS
More terms from Sean A. Irvine, Oct 04 2009
STATUS
approved