A118003 a(n) = largest integer <= n which is coprime to A118002(n-1). a(n) = A118002(n) - A118002(n-1).

1, 2, 2, 4, 5, 5, 7, 7, 8, 10, 11, 11, 13, 13, 14, 16, 17, 17, 19, 19, 20, 22, 23, 23, 25, 25, 26, 28, 29, 29, 31, 31, 32, 34, 35, 35, 37, 37, 38, 40, 41, 41, 43, 43, 44, 46, 47, 47, 49, 49, 50, 52, 53, 53, 55, 55, 56, 58, 59, 59, 61, 61, 62, 64, 65, 65, 67, 67, 68, 70, 71, 71

Offset

1,2

Links

Table of n, a(n) for n=1..72.

Maple

A118002 := proc(nmax) local a, n ; a := [0] ; while nops(a) < nmax do n := nops(a) ; while gcd(n, op(-1, a)) <> 1 do n := n-1 ; od ; a := [op(a), op(-1, a)+n] ; od ; RETURN(a) ; end: a118002 := A118002(100) : for n from 1 to nops(a118002)-1 do printf("%d, ", op(n+1, a118002)-op(n, a118002)) ; od ; # R. J. Mathar, Jun 06 2007

Mathematica

A110802[n_] := A110802[n] = If[n == 0, 0, Module[{a1 = A110802[n-1], k}, For[k = n, True, k--, If[CoprimeQ[a1, k], Return[a1+k]]]]];
a[n_] := A110802[n] - A110802[n-1];
Table[a[n], {n, 1, 72}] (* Jean-François Alcover, Apr 08 2024 *)

Crossrefs

Cf. A118001, A118002.

Sequence in context: A122543 A334149 A369452 * A159296 A277191 A335129

Adjacent sequences: A118000 A118001 A118002 * A118004 A118005 A118006

Keyword

nonn

Author

Leroy Quet, Apr 09 2006

Extensions

More terms from R. J. Mathar, Jun 06 2007

Status

approved