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A088740 Greatest semiprime divisor of n-th composite number. 2
4, 6, 4, 9, 10, 6, 14, 15, 4, 9, 10, 21, 22, 6, 25, 26, 9, 14, 15, 4, 33, 34, 35, 9, 38, 39, 10, 21, 22, 15, 46, 6, 49, 25, 51, 26, 9, 55, 14, 57, 58, 15, 62, 21, 4, 65, 33, 34, 69, 35, 9, 74, 25, 38, 77, 39, 10, 9, 82, 21, 85, 86, 87, 22, 15, 91, 46, 93, 94, 95, 6, 49, 33, 25 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Zak Seidov, Table of n, a(n) for n = 1..1000

MATHEMATICA

Reap[Do[If[! PrimeQ[n], fl = Flatten[Table[#[[1]], {#[[2]]}] & /@ FactorInteger[n]]; Sow[fl[[-1]]*fl[[-2]]]], {n, 4, 1200}]][[2, 1]]; (* Zak Seidov, Mar 18 2013 *)

CROSSREFS

Cf. A088739, A002808, A001358.

Sequence in context: A010300 A113209 A088739 * A088738 A114595 A256415

Adjacent sequences:  A088737 A088738 A088739 * A088741 A088742 A088743

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Oct 12 2003

STATUS

approved

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Last modified April 9 10:52 EDT 2020. Contains 333348 sequences. (Running on oeis4.)