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A120938
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a(0)=1. a(n) = a(n-1) + (largest integer occurring among {a(0),a(1),a(2),...,a(n-1)} that is coprime to n).
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2
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1, 2, 3, 5, 10, 13, 26, 52, 65, 130, 143, 273, 416, 426, 569, 1138, 1707, 3414, 3983, 7966, 11949, 13087, 26174, 38123, 76246, 152492, 190615, 381230, 571845, 1143690, 1181813, 2325503, 4651006, 9302012, 11627515, 20929527, 32557042, 65114084
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OFFSET
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0,2
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LINKS
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EXAMPLE
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Among the terms {a(0),a(1),a(2),a(3),a(4),a(5)}, a(5) = 13 is the largest term that is coprime to 6. So a(6) = a(5) + 13 = 26.
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MAPLE
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A120938 := proc(nmax) local a, cpr, n, i; a := [1, 2]; for n from 3 to nmax do cpr := 0; for i from 1 to n-1 do if gcd(n-1, a[i]) = 1 and a[i] > cpr then cpr := a[i]; fi; od; a := [op(a), a[n-1]+cpr]; od: RETURN(a); end: nmax := 100 : a := A120938(nmax) : for n from 1 to nops(a) do printf("%d, ", a[n]); od; # R. J. Mathar, Aug 17 2006
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PROG
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(PARI) {m=37; print1(a=1, ", "); v=[a]; for(n=1, m, a=0; for(j=1, n, if(gcd(v[j], n)==1&&a<v[j], a=v[j])); print1(a=a+v[n], ", "); v=concat(v, a))} \\ Klaus Brockhaus, Aug 16 2006
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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