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A100576
Smallest difference between distinct prime divisors of the n-th non-prime-power.
2
1, 3, 1, 5, 2, 1, 3, 4, 9, 1, 11, 5, 1, 8, 15, 2, 1, 17, 10, 3, 1, 9, 2, 21, 1, 3, 14, 11, 1, 6, 5, 16, 27, 1, 29, 4, 8, 1, 15, 20, 2, 1, 35, 2, 17, 4, 1, 3, 39, 1, 12, 41, 26, 9, 1, 6, 21, 28, 45, 14, 1, 5, 8, 3, 1, 11, 2, 51, 1, 3, 34, 5, 1, 18, 27, 10, 57, 10, 1, 59, 38, 29, 1, 40, 3, 1, 12
OFFSET
1,2
LINKS
EXAMPLE
6 is the first non-prime-power.
Since 6 = 2*3 and 3-2 = 1, then a(1) = 1.
MATHEMATICA
Min[Differences[FactorInteger[#][[All, 1]]]]&/@ Select[Range[ 2, 150], !PrimePowerQ[ #]&] (* Harvey P. Dale, Jun 22 2021 *)
CROSSREFS
Sequence in context: A176249 A083722 A111426 * A212332 A371750 A131032
KEYWORD
nonn
AUTHOR
Leroy Quet, Jan 02 2005
EXTENSIONS
More terms from Franklin T. Adams-Watters, Aug 29 2006
STATUS
approved