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A076686 a(n)=min(core(n),phi(n)) where core(n) is the squarefree part of n. 0
1, 1, 2, 1, 4, 2, 6, 2, 1, 4, 10, 3, 12, 6, 8, 1, 16, 2, 18, 5, 12, 10, 22, 6, 1, 12, 3, 7, 28, 8, 30, 2, 20, 16, 24, 1, 36, 18, 24, 10, 40, 12, 42, 11, 5, 22, 46, 3, 1, 2, 32, 13, 52, 6, 40, 14, 36, 28, 58, 15, 60, 30, 7, 1, 48, 20, 66, 17, 44, 24, 70, 2, 72, 36, 3, 19, 60, 24, 78, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..80.

FORMULA

sum(k=1, n, a(k)) is asymptotic to c*n^2 with c=0.239......

PROG

(PARI) a(n)=min(core(n), eulerphi(n))

CROSSREFS

Sequence in context: A232626 A322250 A175542 * A114810 A300718 A093819

Adjacent sequences:  A076683 A076684 A076685 * A076687 A076688 A076689

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Oct 25 2002

STATUS

approved

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Last modified May 26 02:56 EDT 2020. Contains 334613 sequences. (Running on oeis4.)