A008345 a(n+1) = a(n)-b(n+1) if a(n) >= b(n+1) else a(n)+b(n+1), where {b(n)} are the triangular numbers A000217.

0, 1, 4, 10, 0, 15, 36, 8, 44, 89, 34, 100, 22, 113, 8, 128, 264, 111, 282, 92, 302, 71, 324, 48, 348, 23, 374, 752, 346, 781, 316, 812, 284, 845, 250, 880, 214, 917, 176, 956, 136, 997, 94, 1040, 50, 1085, 4, 1132, 2308, 1083, 2358, 1032, 2410, 979, 2464, 924

Offset

0,3

Comments

a(0) and a(4) are both zero. Are there any other zero values? - N. J. A. Sloane, Sep 12 2019

Links

Rémy Sigrist, Table of n, a(n) for n = 0..25000 (first 1001 terms from Franklin T. Adams-Watters)

Maple

A008345 := proc(n) option remember; if n = 1 then n-1 elif A008345(n-1) >= n*(n+1)/2 then A008345(n-1)-n*(n+1)/2 else A008345(n-1)+n*(n+1)/2; fi; end;

Mathematica

nxt[{n_, a_}]:=Module[{tr=((n+1)(n+2))/2}, {n+1, If[a>=tr, a-tr, a+tr]}]; Transpose[NestList[nxt, {0, 0}, 50]][[2]] (* Harvey P. Dale, Jun 19 2013 *)

Crossrefs

Cf. A000217, A008344, A076042.

Sequence in context: A331450 A051499 A333654 * A279082 A016488 A087212

Adjacent sequences: A008342 A008343 A008344 * A008346 A008347 A008348

Keyword

nonn,easy

Author

N. J. A. Sloane and J. H. Conway

Status

approved