A104647 a(n) = a(n-1) mod n + a(n-2) mod n; a(0) = 0, a(1) = 1.

0, 1, 1, 2, 3, 5, 8, 6, 6, 12, 8, 9, 17, 13, 16, 14, 14, 28, 24, 14, 18, 32, 28, 14, 18, 32, 24, 29, 25, 25, 50, 44, 30, 41, 37, 8, 9, 17, 26, 43, 29, 31, 60, 48, 20, 23, 43, 66, 61, 29, 40, 69, 57, 20, 23, 43, 66, 52, 60, 53, 53, 106, 97, 77, 46, 58, 104, 95, 63, 89, 82, 29, 39, 68

Offset

0,4

Comments

a(n) <= a(n-1) + a(n-2) < 2*n for n>0, see A105859 for numbers i such that a(i)=a(i-1)+a(i-2) and A105860 for numbers j with a(j)<a(j-1)+a(j-2); - Reinhard Zumkeller, Apr 23 2005

A105855 = (first differences) and A105856 = (partial sums); records occur at A105857: A105858(n) = a(A105857(n)). - Reinhard Zumkeller, Apr 23 2005

Links

Ivan Neretin, Table of n, a(n) for n = 0..10000

Mathematica

Fold[Append[#1, Mod[#1[[-1]], #2] + Mod[#1[[-2]], #2]] &, {0, 1}, Range[2, 73]] (* Ivan Neretin, Jun 18 2018 *)
nxt[{n_, a_, b_}]:={n+1, b, Mod[a, n+1]+Mod[b, n+1]}; NestList[nxt, {1, 0, 1}, 80][[;; , 2]] (* Harvey P. Dale, May 12 2025 *)

Crossrefs

Cf. A079777

Sequence in context: A249188 A284188 A011158 * A065115 A262263 A072987

Adjacent sequences: A104644 A104645 A104646 * A104648 A104649 A104650

Keyword

nonn

Author

Reinhard Zumkeller, Apr 21 2005

Status

approved