A183234 Ordering of the numbers in tree A183232; complement of A183233.

2, 5, 8, 9, 12, 14, 17, 20, 23, 26, 27, 30, 33, 35, 38, 41, 44, 47, 50, 53, 54, 57, 60, 63, 64, 65, 68, 71, 74, 75, 77, 80, 83, 86, 87, 90, 93, 96, 99, 100, 103, 104, 107, 110, 113, 114, 117, 119, 122, 125, 128, 129, 132, 134, 135, 138, 141, 144, 145, 148, 150, 152, 155, 158, 161, 162, 165, 167, 170, 173, 176, 179, 180, 183, 185, 188, 189, 192, 195, 198, 199

Offset

1,1

Links

Table of n, a(n) for n=1..81.

Formula

The monotonic ordering of the numbers in the set S generated by these rules: 2 is in S, and if n is in S, then (n^2+5n+2)/2 and n+Floor(1/2+sqrt(2n+4)) are in S.

Mathematica

nn=200; t={2}; t0=t; While[t=Select[Union[t, (1/2)*(t^2+5t+2), t+Floor[1/2+(2t+4)^(1/2)]], #<=nn&]; t0 !t, t0=t]; t
f[s_List] := Select[ Union@ Join[s, (s^2 + 5 s + 2)/2, s + Floor[1/2 + Sqrt@ (2 s + 4)]], # < 201 &]; NestWhile[f, {2}, UnsameQ, All]

Crossrefs

Cf. A183232, A183233.

Sequence in context: A161154 A174438 A176061 * A108968 A289628 A047387

Adjacent sequences: A183231 A183232 A183233 * A183235 A183236 A183237

Keyword

nonn

Author

Clark Kimberling, Jan 02 2011

Status

approved