A125204 a(0)=0, a(1)=1; and a(n) = a(n-1) + a(a(n-1) mod n) for n>=2.

0, 1, 2, 4, 4, 8, 10, 14, 24, 34, 38, 46, 84, 94, 132, 216, 240, 242, 266, 266, 276, 280, 520, 652, 656, 666, 906, 1122, 1124, 1644, 2300, 2310, 2320, 2358, 2442, 3564, 3564, 3648, 3648, 3928, 3952, 4192, 6634, 6718, 9018, 9284, 12932, 12946, 15388, 15390

Offset: 0

Author

Leroy Quet, Jan 13 2007

Keywords

• nonn

Examples

			a(14) = a(13) + a(a(13) mod 14) = 94 + a(94 mod 14) = 94 + a(10) = 94 + 38 = 132.
		

Links

• N. J. A. Sloane, Table of n, a(n) for n = 0..5000

Programs

Maple

f:=proc(n) option remember;
if n <= 1 then n else f(n-1)+f(f(n-1) mod n); fi; end;
[seq(f(n),n=0..32)]; # N. J. A. Sloane, May 04 2016

Mathematica

f[l_List] := Append[l, l[[ -1]] + l[[Mod[l[[ -1]], Length[l]] + 1]]];Nest[f, {0, 1}, 50] (* Ray Chandler, Jan 23 2007 *)
l = {0, 1}; Do[x = l[[n]] + l[[Mod[l[[n]], n] + 1]]; AppendTo[l, x], {n, 2, 50}]; l (* Ryan Propper, Jan 24 2007 *)

Python

from sympy.core.cache import cacheit
@cacheit
def a(n): return n if n<2 else a(n - 1) + a(a(n - 1)%n)
print([a(n) for n in range(51)]) # Indranil Ghosh, Aug 07 2017

Extensions

Extended by Ray Chandler and Robert G. Wilson v, Jan 23 2007

More terms from Ryan Propper, Jan 24 2007