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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..10000

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

Cf. A088821, A088822, A088824, A088825.

Sequence in context: A260108 A265791 A039679 * A302294 A007445 A159699

Adjacent sequences:  A088820 A088821 A088822 * A088824 A088825 A088826

KEYWORD

nonn

AUTHOR

Labos Elemer, Oct 22 2003

STATUS

approved

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Last modified May 13 12:16 EDT 2021. Contains 343839 sequences. (Running on oeis4.)