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A120610
Sum of previous term and preceding non-divisors.
3
2, 3, 5, 10, 13, 33, 63, 126, 187, 442, 869, 1753, 3506, 5257, 12269, 24538, 36805, 85876, 171755, 343507, 687019, 1374038, 2061055, 4809126, 9618252, 14427378, 28854567, 62518388, 125036840, 250073665, 500147342, 1000294687, 2000589376
OFFSET
1,1
LINKS
FORMULA
a(1) = 2, a(2) = 3, for n>=2, a(n+1) = a(n) + sum_{1<=k<n, a(k) does not divide a(n)} a(k).
MATHEMATICA
s={2, 3}; Do[sum=s[[-1]]; Do[If[!Divisible[s[[-1]], s[[j]]], sum=sum+s[[j]] ], {j, k-1}]; AppendTo[s, sum] , {k, 2, 32}]; s (* James C. McMahon, Oct 07 2024 *)
CROSSREFS
Cf. A120611.
Sequence in context: A071848 A268176 A120938 * A090859 A004681 A338589
KEYWORD
nonn
AUTHOR
STATUS
approved