A125554 a(0)=2. a(n) = the a(n-1)th integer from among those positive integers coprime to n.

2, 2, 3, 4, 7, 8, 23, 26, 51, 76, 189, 207, 619, 670, 1563, 2929, 5857, 6223, 18667, 19704, 49259, 86203, 189645, 198265, 594793, 743491, 1610897, 2416345, 5638137, 5839499, 21898121, 22628058, 45256115, 74672590, 158679253, 231407243

Offset

0,1

Links

Table of n, a(n) for n=0..35.

Example

The positive integers coprime to 6 are 1,5,7,11,13,17,19,23,25,29,31,...Since a(5) = 8, a(6) is 23, the 8th integer in the sequence of positive integers coprime to 6.

Maple

copr := proc(i, n) local res, j ; res := 1 ; j := 1; while j<i do res := res+1 ; while gcd(res, n) > 1 do res := res+1 ; od ; j := j+1 ; od ; RETURN(res) ; end; A125554 := proc(nmax) local a, anext; a := [2] ; while nops(a) < nmax do anext := copr(op(-1, a), nops(a)) ; a := [op(a), anext] ; od ; RETURN(a) ; end ; A125554(26) ; # R. J. Mathar, Jan 07 2007

Mathematica

f[m_, n_] := Block[{k, c, x}, x = Floor[m/EulerPhi[n]] - 1; k = x*n; c = m - x*EulerPhi[n]; While[c > 0, k++; While[GCD[k, n] > 1, k++ ]; c--; ]; k]; g[l_List] := Append[l, f[l[[ -1]], Length[l]]]; Nest[g, {2}, 36] (* Ray Chandler, Jan 05 2007 *)

Crossrefs

Sequence in context: A276526 A091605 A145468 * A345867 A252796 A083130

Adjacent sequences: A125551 A125552 A125553 * A125555 A125556 A125557

Keyword

nonn

Author

Leroy Quet, Dec 30 2006

Extensions

Extended by Ray Chandler, Jan 05 2007

Status

approved