OFFSET
1,3
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MAPLE
a[1]:=1: for n from 2 to 80 do b[n]:=[seq(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..80);
MATHEMATICA
a[1] = 1; a[n_] := a[n] = Plus @@ GCD[Table[i, {i, n - 1}], a[n - 1]]; Table[ a[n], {n, 62}] (* Robert G. Wilson v, Dec 09 2004 *)
nxt[{n_, a_}]:={n+1, Total[GCD[Range[n], a]]}; NestList[nxt, {1, 1}, 70][[All, 2]] (* Harvey P. Dale, Sep 10 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Dec 06 2004
EXTENSIONS
More terms from Emeric Deutsch and Robert G. Wilson v, Dec 09 2004
Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, Jun 16 2007
STATUS
approved