A117534 Inverse permutation to sequence A117532 (if indeed sequence A117532 is a permutation of the positive integers).

1, 2, 5, 3, 9, 4, 6, 7, 13, 8, 10, 11, 16, 12, 14, 19, 15, 17, 21, 18, 25, 20, 22, 23, 28, 24, 26, 31, 27, 29, 33, 30, 37, 32, 34, 35, 40, 36, 38, 43, 39, 41, 45, 42, 49, 44, 46, 47, 52, 48, 50, 55, 51, 53, 57, 54, 61, 56, 58, 59, 62, 63, 65, 60, 69, 64, 66, 67, 73, 68, 70, 71

Offset

1,2

Links

Jean-François Alcover, Table of n, a(n) for n = 1..3000

Maple

read("transforms") ; A117532 := proc(nmax) local a, n, nxt, asu ; a := [1] ; asu := 1 ; while nops(a) < nmax do n := nops(a)+1 ; nxt := 1 ; while nxt in a or gcd(n, asu+nxt) <> 1 do nxt := nxt+1 ; od ; a := [op(a), nxt] ; asu := asu+nxt ; od ; a ; end: A117532(180) ; INVERSE(%) ; # R. J. Mathar, Jul 20 2009

Mathematica

(* b(n) is A117532 *)
nmaxa = 72; nmaxb = nmaxa + 3;
(* nmaxb can be increased in case less than nmaxa terms are produced *)
b[n_] := b[n] = If[n == 1, 1, bb = Array[b, n-1]; For[k = 2, True, k++, If[FreeQ[bb, k] && CoprimeQ[n, Total[bb]+k], Return[k]]]];
Do[a[b[n]] = n, {n, 1, nmaxb}];
TakeWhile[Table[a[n], {n, 1, nmaxa}], IntegerQ] (* Jean-François Alcover, Nov 18 2024 *)

Crossrefs

Cf. A117532, A117533.

Sequence in context: A332354 A159988 A134880 * A256628 A112990 A169848

Adjacent sequences: A117531 A117532 A117533 * A117535 A117536 A117537

Keyword

nonn,changed

Author

Leroy Quet, Mar 26 2006

Extensions

More terms from R. J. Mathar, Jul 20 2009

Status

approved