A124195 a(1)=1. a(n) = n - GCD(a(n-1),n).

1, 1, 2, 2, 4, 4, 6, 6, 6, 8, 10, 10, 12, 12, 12, 12, 16, 16, 18, 18, 18, 20, 22, 22, 24, 24, 24, 24, 28, 28, 30, 30, 30, 32, 34, 34, 36, 36, 36, 36, 40, 40, 42, 42, 42, 44, 46, 46, 48, 48, 48, 48, 52, 52, 54, 54, 54, 56, 58, 58, 60, 60, 60, 60, 60, 60, 66, 66, 66, 68, 70, 70, 72

Offset

1,3

Comments

a(n) is even for n >= 3. a(n+1) >= a(n). - Robert Israel, Apr 18 2024

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

A[1]:= 1:
for n from 2 to 100 do A[n]:= n - igcd(A[n-1], n) od:
seq(A[i], i=1..100); # Robert Israel, Apr 18 2024

Mathematica

f[l_List] := Block[{n = Length[l] + 1}, Append[l, n - GCD[l[[ -1]], n]]]; Nest[f, {1}, 75] (* Ray Chandler, Dec 11 2006 *)
RecurrenceTable[{a[1]==1, a[n]==n-GCD[a[n-1], n]}, a, {n, 80}] (* Harvey P. Dale, Jul 05 2013 *)

Crossrefs

Sequence in context: A083535 A250983 A070320 * A220662 A079584 A179291

Adjacent sequences: A124192 A124193 A124194 * A124196 A124197 A124198

Keyword

nonn,changed

Author

Leroy Quet, Dec 06 2006

Extensions

Extended by Ray Chandler, Dec 11 2006

Status

approved