1,2

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).

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

(Haskell)

a227288 n = a227288_list !! (n-1)

a227288_list = zipWith gcd (tail a227113_list) a227113_list

Sequence in context: A130008 A101809 A127203 * A126132 A129982 A052552

Adjacent sequences: A227285 A227286 A227287 * A227289 A227290 A227291

nonn

Reinhard Zumkeller, Jul 05 2013

approved