A336604 a(0) = 1, a(1) = 2; thereafter let x = (a(n-1) mod a(n-2)); then a(n) = a(n-1) + a(x) if x < n, otherwise a(n) = a(n-1).

1, 2, 3, 5, 8, 13, 26, 27, 29, 32, 37, 50, 50, 51, 53, 56, 61, 74, 125, 125, 126, 128, 131, 136, 149, 200, 200, 201, 203, 206, 211, 224, 275, 275, 276, 278, 281, 286, 299, 350, 350, 351, 353, 356, 361, 374, 425, 425, 426, 428, 431, 436, 449, 500, 936, 936, 937, 939, 942, 947, 960, 1011

Offset

0,2

Links

N. J. A. Sloane, Table of n, a(n) for n = 0..20000

Example

a(7) = 27, a(8) = 29, so a(9) = 29 + a(29 mod 27) = 32.

Maple

a:= proc(n) option remember; `if`(n<2, n+1, (x->
      a(n-1)+`if`(x<n, a(x), 0))(a(n-1) mod a(n-2)))
    end:
seq(a(n), n=0..100);  # Alois P. Heinz, Oct 25 2020

Mathematica

a[0] = 1; a[1] = 2; a[n_] := a[n] = a[n - 1] + If[(r = Mod[a[n - 1], a[n - 2]]) < n, a[r], 0]; Array[a, 51, 0] (* Amiram Eldar, Oct 10 2020 *)

Prog

(C++)
for (int i = 2; i < 10000; i++)
    {
        j = a[i - 1];
        k = a[i - 2];
        l = j % k;
        if (int(l) <= int(i)) a[i] = j + a[l]; else a[i] = a[i - 1];
    }

Crossrefs

Cf. A215526.

Sequence in context: A125730 A340708 A074030 * A024318 A324738 A132915

Adjacent sequences: A336601 A336602 A336603 * A336605 A336606 A336607

Keyword

nonn

Author

Maxim Skorohodov, Oct 10 2020

Status

approved