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A100674
a(1) = 1; a(n+1) = Sum_{k=1..n} a(gcd(k, a(n))).
1
1, 1, 2, 3, 5, 9, 8, 9, 10, 13, 10, 27, 24, 59, 14, 80, 127, 17, 144, 169, 43, 21, 84, 183, 32, 126, 184, 140, 441, 124, 44, 74, 32, 209, 204, 463, 36, 617, 38, 798, 1025, 1124, 62, 86, 105, 422, 46, 551, 774, 222, 157, 51, 476, 820, 1492, 81, 470, 186, 183, 78, 459, 884
OFFSET
1,3
LINKS
MAPLE
a[1]:=1: for n from 2 to 70 do b[n]:=[seq(a[gcd(k, a[n-1])], k=1..n-1)]: a[n]:=sum(b[n][j], j=1..nops(b[n])) od: seq(a[n], n=1..70);
MATHEMATICA
a[1] = 1; a[n_] := a[n] = Plus @@ a /@ GCD[Range[n - 1], a[n - 1]]; Table[ a[n], {n, 62}] (* Robert G. Wilson v, Dec 09 2004 *)
PROG
(GAP) a:=[1];; for n in [2..65] do a[n]:=Sum([1..n-1], k->a[Gcd(k, a[n-1])]); od; a; # Muniru A Asiru, Oct 21 2018
CROSSREFS
Sequence in context: A324886 A277332 A342456 * A058314 A072735 A127149
KEYWORD
nonn
AUTHOR
Leroy Quet, Dec 06 2004
EXTENSIONS
More terms from Emeric Deutsch and Robert G. Wilson v, Dec 09 2004
STATUS
approved