A178853 "Josephus problem": n persons stand in a circle and eliminate every seventh person counting clockwise until only person a(n) is remaining.

1, 2, 3, 2, 4, 5, 5, 4, 2, 9, 5, 12, 6, 13, 5, 12, 2, 9, 16, 3, 10, 17, 1, 8, 15, 22, 2, 9, 16, 23, 30, 5, 12, 19, 26, 33, 3, 10, 17, 24, 31, 38, 2, 9, 16, 23, 30, 37, 44, 1, 8, 15, 22, 29, 36, 43, 50, 57, 5, 12, 19, 26, 33, 40, 47, 54, 61, 68, 6, 13, 20, 27, 34, 41, 48, 55, 62, 69, 76

Offset: 1

Author

Roland Schroeder (florola(AT)gmx.de), Jun 18 2010

Keywords

• nonn

Comments

Several other versions of this sequence are already in the OEIS. - N. J. A. Sloane, Jun 24 2010

Links

• Leonhard Euler, Observationes circa novum et singulare progressionum genus. In: Novi Comment. Akadem. Petropol. Vol.20 (1775).
• Eric Weisstein's World of Mathematics, Josephus Problem.
• Index entries for sequences related to the Josephus Problem.

Crossrefs

Cf. A005427, A006257.

Programs

Mathematica

Needs["Combinatorica`"]
a[n_] := Last@ InversePermutation@ Josephus[n, 7]; Array[a, 79] (* Robert G. Wilson v, Jul 31 2010 *)

Extensions

a(29) onwards from Robert G. Wilson v, Jul 31 2010