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A129090 a(1)=1; a(n) = gcd(a(n-1), n) + lcm(a(n-1), n). 1
1, 3, 6, 14, 71, 427, 434, 1738, 15643, 156431, 156442, 938654, 12202503, 170835043, 2562525646, 20500205170, 348503487891, 2091020927349, 39729397619632, 198646988098164, 1390528916687151, 30591636167117323, 703607631843698430 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..23.

MAPLE

a[1]:=1: for n from 2 to 30 do a[n]:=gcd(a[n-1], n)+lcm(a[n-1], n) od: seq(a[n], n=1..27); # Emeric Deutsch, Apr 13 2007

MATHEMATICA

k = 1; Do[Print[k]; k = GCD[k, n] + LCM[k, n], {n, 2, 30}] (* Ryan Propper, Apr 07 2007 *)

CROSSREFS

Cf. A129091.

Sequence in context: A054099 A257320 A318344 * A058141 A144654 A132279

Adjacent sequences:  A129087 A129088 A129089 * A129091 A129092 A129093

KEYWORD

nonn

AUTHOR

Leroy Quet, Mar 29 2007

EXTENSIONS

More terms from Ryan Propper and Emeric Deutsch, Apr 07 2007

STATUS

approved

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Last modified January 20 03:32 EST 2019. Contains 319323 sequences. (Running on oeis4.)