A271773 a(1) = 0, then a(n) is the maximum of all 0 < m < n for which n == a(m) (mod m).

0, 1, 2, 1, 4, 1, 6, 3, 5, 1, 10, 1, 12, 9, 2, 1, 16, 1, 18, 7, 11, 1, 22, 5, 13, 3, 20, 1, 28, 1, 30, 21, 17, 7, 8, 1, 36, 25, 5, 1, 40, 1, 42, 39, 23, 1, 46, 7, 16, 33, 14, 1, 52, 11, 48, 19, 29, 1, 58, 1, 60, 15, 38, 13, 54, 1, 66, 45, 7, 1, 70, 1, 72, 27

Offset: 1

Author

Peter Kagey, Apr 14 2016

Keywords

• nonn

Examples

			a(1) = 0 by definition.
a(2) = 1 because a(1) == 2 (mod 1).
a(3) = 2 because a(2) == 3 (mod 2).
a(4) = 1 because a(1) == 4 (mod 1).
a(5) = 4 because a(4) == 5 (mod 4).
a(6) = 1 because a(1) == 6 (mod 1).
a(7) = 6 because a(6) == 7 (mod 6).
a(8) = 3 because a(3) == 8 (mod 3).
		

Links

• Peter Kagey, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A269423, A269427, A271530, A271531, A271774.

Programs

Mathematica

a[1] = 0; a[n_] := a[n] = Max@ Select[Range[n - 1], Mod[n, #] == Mod[a[#], #] &]; Table[a@ n, {n, 75}] (* Michael De Vlieger, Apr 15 2016 *)