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A098426 a(n)=(1/2)*sum(i=0,n,rad(binomial(n,i))) where rad(k)=A007947(k). 0
1, 2, 4, 6, 16, 27, 64, 66, 94, 287, 1024, 645, 2380, 6723, 12094, 7136, 36772, 38733, 161254, 241083, 571714, 1203173, 4194304, 2005009, 2162496, 8739877, 6699838, 27330423, 112844656, 41322885, 252807388, 201501336, 419398108, 2840231975 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

For n>1 a(n) odd seems to imply 2*phi(n)<n where phi= totient function.

LINKS

Table of n, a(n) for n=1..34.

CROSSREFS

Sequence in context: A076075 A030157 A162580 * A279480 A045665 A133492

Adjacent sequences:  A098423 A098424 A098425 * A098427 A098428 A098429

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Oct 26 2004

STATUS

approved

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Last modified April 7 00:55 EDT 2020. Contains 333291 sequences. (Running on oeis4.)