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URL: https://oeis.org/A088823

⇱ A088823 - OEIS

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A088823
a(n) is the GCD of the sum of largest prime factors of numbers from 1 to n and of the sum of smallest prime factors of numbers from 1 to n.
3
0, 2, 5, 7, 12, 1, 1, 1, 1, 4, 1, 1, 1, 2, 1, 1, 6, 1, 1, 1, 4, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 3, 4, 1, 3, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 10, 1, 1, 1, 2, 29, 1, 1, 2, 1, 7, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 3, 1, 1, 2, 1, 5, 1, 14, 1, 1
OFFSET
1,2
LINKS
FORMULA
a(n) = gcd(A088821(n), A088822(n)).
MAPLE
map(igcd@op, ListTools:-PartialSums([[0, 0], seq([min, max](numtheory:-factorset(n)), n=2..N)])); # Robert Israel, Dec 16 2015
MATHEMATICA
GCD @@@ Transpose[{Accumulate[Prepend[First /@ #, 0]], Accumulate[Prepend[Last /@ #, 0]]}] &@ Map[First /@ FactorInteger@ # &, Range[2, 103]] (* Michael De Vlieger, Dec 15 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Oct 22 2003
STATUS
approved