A141126 a(n+1) = a(n)-n^2 if positive and new, else a(n+1) = a(n)+n^2; a(0)=1.

1, 1, 2, 6, 15, 31, 56, 20, 69, 5, 86, 186, 65, 209, 40, 236, 11, 267, 556, 232, 593, 193, 634, 150, 679, 103, 728, 52, 781, 1565, 724, 1624, 663, 1687, 598, 1754, 529, 1825, 456, 1900, 379, 1979, 298, 2062, 213, 2149, 124, 2240, 4449, 2145, 4546, 2046, 4647

Offset: 0

Author

Reinhard Zumkeller, Jun 05 2008

Keywords

• nonn

Links

• Indranil Ghosh, Table of n, a(n) for n = 0..50000 (terms 0..240 from Reinhard Zumkeller)
• Index entries for sequences related to Recamán's sequence.

Crossrefs

Cf. A063733.

Programs

Mathematica

s={1};Do[nx=s[[-1]]-n^2;If[nx>0&&!MemberQ[s,nx],AppendTo[s,nx],AppendTo[s,nx+2n^2]],{n,0,51}];s (* James C. McMahon, Jul 17 2025 *)