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A113925 a(1)=0. a(1)=1. a(n+2) = gcd(a(n+1) + a(n), n). 2
0, 1, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 3, 5, 1, 6, 1, 1, 1, 2, 1, 3, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 3, 5, 1, 6, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

a(1)'s value is arbitrary. Replacing a(1) with any integer would not alter the rest of the sequence.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

a(14) = gcd(a(13) + a(12), 12) = gcd(1+2, 12) = gcd(3, 12) = 3.

MAPLE

a[1]:=0: a[2]:=1: for n from 3 to 135 do a[n]:=gcd(a[n-1]+a[n-2], n-2) od: seq(a[n], n=1..117); # Emeric Deutsch, Feb 07 2006

MATHEMATICA

nxt[{n_, a_, b_}]:={n+1, b, GCD[a+b, n-1]}; NestList[nxt, {2, 0, 1}, 110][[All, 2]] (* Harvey P. Dale, Jun 13 2017 *)

CROSSREFS

Sequence in context: A135508 A030413 A139434 * A328231 A180466 A105083

Adjacent sequences:  A113922 A113923 A113924 * A113926 A113927 A113928

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 30 2006

EXTENSIONS

More terms from Emeric Deutsch, Feb 07 2006

STATUS

approved

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Last modified August 7 19:57 EDT 2020. Contains 336279 sequences. (Running on oeis4.)