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A227288 Greatest common divisor of consecutive terms in A227113. 3
1, 2, 1, 3, 1, 5, 1, 7, 2, 4, 3, 3, 1, 11, 1, 13, 2, 2, 1, 17, 1, 19, 2, 4, 3, 3, 1, 23, 1, 5, 2, 4, 1, 29, 1, 31, 1, 3, 1, 5, 1, 37, 1, 3, 1, 41, 1, 43, 2, 4, 3, 5, 1, 47, 1, 7, 1, 3, 2, 4, 1, 53, 1, 5, 1, 3, 1, 59, 1, 61, 2, 2, 1, 67, 2, 2, 1, 3, 1, 71, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = GCD(A227113(n),A227113(n+1));

a(2*n) > 1 by definition of A227113;

9 is the smallest odd number m with a(m) > 1: a(9) = GCD(A227113(9),A227113(10)) = GCD(14,8) = 2;

a(A227289(n)) = n and a(m) <> n for m < A227289(n).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

PROG

(Haskell)

a227288 n = a227288_list !! (n-1)

a227288_list = zipWith gcd (tail a227113_list) a227113_list

CROSSREFS

Sequence in context: A130008 A101809 A127203 * A126132 A129982 A052552

Adjacent sequences:  A227285 A227286 A227287 * A227289 A227290 A227291

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 05 2013

STATUS

approved

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Last modified October 23 13:38 EDT 2019. Contains 328345 sequences. (Running on oeis4.)