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A175307 a(n) = the number of terms in row n of A175306. 2
2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 4, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1, 3, 1, 2, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(2n) = 1, and a(3n)=1, for all positive integers n.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

A175307:=proc(n)

local R, last, k, P;

R:= n;

last:= n;

P:= n;

while igcd(last, 6)=1 do

  for k from last+1 do

    if igcd(k-1, P) = 1 and igcd(k, P) = 1 and igcd(k+1, P) =1 then

      R:= R, k; last:= k; P:= P*k; break

    fi

  od

od;

nops([R])

end proc:

map(A175307, [$1..100]); # Robert Israel, Feb 10 2017

CROSSREFS

Cf. A175306

Sequence in context: A276949 A205794 A241665 * A316557 A032436 A280274

Adjacent sequences:  A175304 A175305 A175306 * A175308 A175309 A175310

KEYWORD

nonn

AUTHOR

Leroy Quet, Mar 26 2010

STATUS

approved

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Last modified December 11 04:29 EST 2018. Contains 318049 sequences. (Running on oeis4.)